Wednesday, December 9, 2015

Where's The Rain Going To Go?

 When rainstorms come pouring through California each winter, think about this: Where is all that water going when it lands in your backyard? Here are some tips to protect your house, pool cover and prized outdoor plants located in low lying areas:

• Enjoy the rain...from indoors. Do as little as possible in the garden during a downpour. Working in wet soil causes compaction. 


• Add gutter extensions to move water away from the house. These sections of flexible pipe allow you to divert water several feet away from plants that don't like wet feet. And, it may keep your house foundation drier, too.


• Get a submersible sump pumpto move water in a hurry from pool covers and planted areas that flood. Some models are water activated (they automatically come on when the water level rises an inch or so). Place the sump pump on a board to keep dirt from clogging the filtration screen.

• Dig a hole. A hole (also called a sump) that is dug in the lowest portion of your yard, a hole that penetrates through all the layers of hardpan (usually 2-4 feet below the surface), can help drain away storm water. Line the hole with a non-porous material (hard plastic sheeting, for example) to keep the surrounding dirt from falling back into the hole. Fill the hole with small rocks, about one inch in diameter.

• Construct an underground hard drain or a French drain (perforated drain pipe or gravel creek bed). If it's the lawn area that's flooding, dig a trench and lay a drain line in the lowest area of the lawn. Don't do any digging immediately after a heavy rain, though; wait until the soil dries enough to avoid unnecessary soil compaction. Be sure to slope the perforated drain pipe, allowing at least a one foot drop for each 100 feet of length (one quarter-inch per foot). Dig backwards from where the water will exit the pipe, trenching back towards the source of flooding to help determine how deep to lay the drain pipe. Line the trench with a few inches of gravel, both above and below the pipe. For a lawn area, try to lay the pipe at least two feet below the surface.

• If it's the garden bed that's flooding, consider building raised beds this fall, lining the bed with 2X8, 2X10 or 2X12 redwood planks. Capping off the top of these boards with 2X6 redwood will give you a comfortable place to sit while harvesting vegetables and pulling weeds.


• If you haven't planted in a flooded area yet, consider creating mounds first, planting trees and shrubs on the top of the mounds.

 If you're still stuck with pools of standing water after heavy rains despite your best efforts, consider planting trees and shrubs that can take "wet feet". Water-tolerant trees for many areas of Northern and Central California include sweet gum, magnolia, and tupelo. Shrubs for wet areas include thuja and red twig dogwood.

Saturday, December 5, 2015

Hard Freeze in the Forecast? Here's What To Do, Before and After

Frost, Freeze, Hard Freeze: Yes, they are all words that can make you shiver. But for gardeners, the preparation level in the yard goes from not stepping on the lawn in the morning (grass blades can break under your weight, even during a light frost) to madly rushing around the premises to protect plants, pets, and water lines when a hard freeze is forecast.

 First, some widely accepted definitions of those terms:

Frost: temperatures dip to 32 °F (0 °C) for short periods of time. Occurs with fair skies and light winds.

Freeze: temperatures at or below 32 °F

Hard Freeze: temperatures below 28 °F for several hours.

In the Sacramento area, the typical frost/freeze season is from late November to early February. However, frosts have been recorded as early as the first week of November and as late as the last week of March.
Here's a last minute checklist for your home and garden if the TV weather people (or panicky bloggers) tell you the morning low will be in the mid-20's, for several hours:
• If it hasn't rained, water plants thoroughly, especially container plants.

• If possible, move sensitive container plants next to a south or west facing wall.


Agribon Frost Cloth Protecting Meyer Lemon Tree
• Cover citrus and other sensitive plants with burlap, row cover fabric (such as Agribon) or sheets (be sure to keep the sheets dry). Tent plastic sheets over the plants; don't let plastic touch plant leaves. A light bulb placed in such a plant can offer a few degrees of protection. For best protection, sheets should reach all the way to the ground around citrus trees and other freeze-susceptible plants.
• If using an anti-transpirant polymer coating material such as Wilt-Pruf or Cloud Cover, apply at the warmest time of the day, or at least six hours before an expected frost. Read and follow all label directions. If using these products, thoroughly water the plant before applying.

• Disconnect hoses and drip lines, removing end caps. Lay out straight.

• To prevent broken grass blades, don't walk on a frozen lawn.

• Remove the lowest sprinkler head to drain.

Protect exposed pipes around wells and pumps

• Cover unprotected faucets and pipes, including any spa or pool equipment.


• To prevent frozen attic pipes, let lukewarm water trickle out of the indoor faucet farthest from the inlet. Also, let faucets with pipes running along an outer, north facing wall trickle during the night.  
• Open cabinet doors to get more heat to the pipes. Close the garage door if water pipes pass through the garage.

• Setting your thermostat nightly at 55 can add needed heat to the attic pipes.

• If leaving the house for a vacation during an expected freeze, turn off the water to the house, and open up the faucet farthest from the inlet. Be sure to turn off your water heater.

• To prevent cracking tile, run your pool and spa equipment during the freezing hours. 

• Don't forget about your pets during a prolonged freeze. Bring them indoors at night. Move or replace their drinking water. Break up any frozen water in bird baths. 


• Cover the worm bin, too!

After a hard freeze, panicky gardeners should fight the urge to clean up the garden. The best strategies after a hard freeze? 
• Make sure all plants, especially container plants that are protected by overhangs, have been irrigated. Moist soil can protect the roots of suffering plants better than dry soil if more cold snaps hit. 
• Don't prune away any damaged portions of plants.

If plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors.

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. 

It may take until mid-Spring before you see new growth. Patience is key before you pick up the pruners. In the meantime, tolerate the ugly.

Make sure your garden and potted plants remain moist, especially if it isn't raining. Water gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

Some of those dead plants may be summer annuals. Say goodbye to the tomatoes, impatiens, marigolds, squash, and others. Mornings hovering around 25 degrees can do that to these summer annuals. Put them in the compost pile; purchase and plant more in the spring, after all danger of frost.

Friday, November 27, 2015

Saving the Tomatoes of Late Fall

Kathy writes: "I have a ‘Better Boy’ that after a lull over the summer started producing again! It’s full of green tomatoes in various sizes. Since it looks like the temps are going to dip pretty low in the next few days, should I pick the larger ones and let them ripen inside? Enquiring minds need to know……"


I read an intriguing garden column in the Redding, CA newspaper that suggested one way to get tomatoes to ripen outdoors now. It said: "A rule of thumb is, in the fall, take off all leaves and stems and all fruit that will not have time to develop before frost. You'll end up with skeletal vines and bare fruit, which is exactly what you want, since now all the plant's energy will go into ripening that fruit."

That might work in the mild climate areas of southern California, but here in Northern California, you're asking for a quicker end to tomato season if you do that. October-November temperatures are typically dipping down into the 40's here; in November, nighttime lows in the 30's are quite likely. When nighttime temperatures are in the 40's and below, fruit development slows to a crawl and causes other problematic issues.  
Even here in the milder Sacramento region, harvesting red tomatoes in mid-November is an iffy proposition, at best. The typical Sacramento gardener Thanksgiving trick: harvest the remaining tomatoes the day before. Immediately cut off the damaged, ugly portions. Serve the miniscule, pretty remains to Thursday's dinner guests, chopped and mixed into a salad. 
"Why yes, we can harvest tomatoes on Thanksgiving!" Please don't ask to see the whole tomatoes, though. You might lose your appetite.

As the fall weather finally begins to turn cooler, gardeners are faced with this annual dilemma: will those green tomatoes in the garden ripen?
In many areas of California, fresh garden tomatoes remain edible until late October or early November. They may not be pretty...but they are still a heckuva lot tastier than any tomato you'll find in a grocery store. By mid-November, remaining tomatoes are subject to harsher, colder, wetter weather leading to more outbreaks of blight diseases, insect infestations and bird pecking.

Are you tempted to harvest those green tomatoes, now, hoping they'll ripen up indoors? Here are a few tips.

From the Texas A&M page, 
Tomato, Part I (Questions 1 - 41):

How do you tell when a green tomato, harvested early to prevent freeze damage, will ever turn red and ripen? This can simply be done with a sharp kitchen knife. Harvest a tomato typical of the majority of green tomatoes on your plants. Look at size but pay particular attention to fruit color. Slice through the center of the tomato. Closely examine the seed within the fruit. If the seeds are covered with a clear gel which cause them to move away from the knife, then that fruit will eventually turn red and ripen. If the seeds are cut by the knife then those fruit will never properly ripen. Compare the color and size of the tested fruit when harvesting tomatoes on your plants. Most similar fruit will eventually ripen and turn red.

Cooler September temperatures help fruit to ripen because the red tomato pigments, lycopene and carotene, are not produced above 85 degrees F; nor is lycopene below 50 degrees F.

As late September approaches, gardeners often try to extend the life of their plants by covering with cloth or plastic. Covering plants works well for nearly red tomatoes, but not as well for mature green ones. 

Though foliage may sometimes be saved, research shows that chilling injury on green fruit occurs at temperatures of 50 degrees and decay losses rise markedly on fruit exposed to 40 degrees F. Red ones well on their way to ripening tolerate colder temperatures.

Before frost hits and plants go down, pick and bring fruit indoors to ripen. Clip fruit with a very short stem piece left on but one that’s not long enough to punch holes in other tomatoes. Stems ripped out of fruit will open them to decay.
Eliminate (immature) green fruit, as research shows it’s more likely to spoil than ripen and never develops the flavor consumers want anyway. Mature green fruit will develop good flavor. Mature green tomatoes are well sized and have turned light green to white. If cut open, seeds are encased in gel and no empty cavity space is present.

In addition to mature green, sort and store fruit by these groups as they will ripen at similar speeds. Fruit may be "turning" with a tinge of pink color showing, "pink" with 30 to 60 percent color showing, "light red" with 60 to 90 percent color present, and others "fully red" but not soft.

Store mature green tomatoes at 55 to 70 degrees F. Once fruit is fully ripe, it can be stored at 45 to 50 degrees F with a relative humidity of 90 – 95%. 

Recommended refrigerator operating temperatures of 40 degrees are certainly too cool to ripen mature green tomatoes and are colder than desired for ripe ones. Ripening enzymes are destroyed by cold temperatures whether in the garden or in a refrigerator.
Ripen tomatoes in well-ventilated, open cardboard boxes at room temperature checking them every few days to eliminate those that may have spoiled. Mature green tomatoes will ripen in 14 days at 70 degrees F and 28 days at 55 degrees F.
The folks at UC Davis recommend storing a small amount of green tomatoes in a carton box on fiber trays or paper layers.
One way to add some air circulation to the bottom, especially in warm conditions: store the tomatoes in a fruit box that contains a perforated plastic liner.

Hobby farmer Linsey Knerl offers these ideas for saving green tomatoes:

Get a rope. By pulling up your plants (root and all, if possible) and hanging them right-side up in a garage or basement, you can prolong their time on the vine for a few more weeks. Just string up some clothesline or heavy rope across one wall, and clip the tops of the plant to the rope with clothespins or binder clips. Try to avoid too much sunlight, or your tomatoes will spoil or ripen unevenly. A temperature of 60-72 degrees is ideal. 
Go the paper route. 
My grandma used this trick to ripen up green ones over a period of a week or two. Pick only the green tomatoes without cracks, holes, or blight, wrap them individually in newspaper, and place them in a single layer in the bottom of a wooden crate or basket. 


And you can always cook 'em, such as with this recipe for Fried Green Tomatoes from :

        4 large green tomatoes
        2 eggs
        1/2 cup milk
        1 cup all-purpose flour
        1/2 cup cornmeal
        1/2 cup bread crumbs
        2 teaspoons coarse kosher salt
        1/4 teaspoon ground black pepper
        1 quart vegetable oil for frying
    1.    Slice tomatoes 1/2 inch thick. Discard the ends.

    2.    Whisk eggs and milk together in a medium-size bowl. Scoop flour onto a plate. Mix cornmeal, bread crumbs and salt and pepper on another plate. Dip tomatoes into flour to coat. Then dip the tomatoes into milk and egg mixture. Dredge in breadcrumbs to completely coat.

    3.    In a large skillet, pour vegetable oil (enough so that there is 1/2 inch of oil in the pan) and heat over a medium heat. Place tomatoes into the frying pan in batches of 4 or 5, depending on the size of your skillet. Do not crowd the tomatoes, they should not touch each other. When the tomatoes are browned, flip and fry them on the other side. Drain them on paper towels.

FOR A HEALTHIER ALTERNATIVE...(and you knew this was coming) try this vegan green tomato recipe from the Fat Free Vegan Kitchen Blog:

Oven-Fried Green Tomatoes


1/2 cup water
1 1/2 teaspoon ground flax seed
1/2 cup cornmeal
1/4 cup quinoa flour (or other flour)
1 teaspoon cornstarch (or other starch)
1/2 teaspoon black pepper freshly ground
1/2 teaspoon salt
4 large green tomatoes

Preheat oven to 425. Spray a baking sheet lightly with canola oil or non-stick spray or line with parchment paper.
Combine the water and ground flax seeds in a blender and blend at high speed for 30 seconds. Pour into a wide, shallow bowl and allow to sit for a few minutes to thicken slightly.
In another wide bowl or plate, combine remaining ingredients (except tomatoes). Cut tomatoes into slices about 1/4 to 1/2-inch thick. Submerge a tomato slice in the flax-water, allow excess to drip off, and place slice into cornmeal mixture. Press lightly to make sure that bottom of slice is covered with cornmeal and turn to coat other side. Place on prepared baking sheet.
When all tomato slices are coated, bake for 15 minutes, or until bottoms are golden brown. Turn and bake another 15 minutes to brown other side. Remove from oven and serve immediately.
Preparation time: 25 minute(s) | Cooking time: 30 minute(s)

Number of servings (yield): 6

Nutrition (per serving): 94 calories, 12 calories from fat, 1.4g total fat, 0mg cholesterol, 214.6mg sodium, 287.3mg potassium, 18.7g carbohydrates, 2.8g fiber, 5.1g sugar, 3.2g protein. 

Monday, November 23, 2015

Rain, Frost, Freeze? Welcome to Late November, Citrus Tree Owners!

Heading out for grandma's house for Thanksgiving Week? We are now officially entering the shivering season for the Central Valley, Bay Area and low foothills. Late November through mid-February is the most critical time here for protecting frost-susceptible plants.
Not a rare, white weeping fig. More like "frozen fig"

Don't let your citrus trees and other frost sensitive plants (such as the freeze damaged weeping fig, above) get caught by a "Turkey Day Surprise" while you're away. Morning lows will be dipping into the upper 20's and low 30's. The National Weather Service is predicting rain for Northern California for Tuesday and Wednesday, with snow levels dropping to near 2000 feet in the Sierra foothills. When the rain blows out Wednesday night, more colder air is coming in for Thanksgiving, Friday and Saturday. Overnight lows are forecast to dip below freezing, with frost and a freeze highly likely...depending where you live, and where you're citrus trees reside. 

All gardening is local. That thermometer on the window or door frame of your house? It's showing the temperature at that particular point on your property. And, it's probably showing a reading that is getting a boost from the heat that's escaping your house. On the other hand, the temperature where your citrus trees are located is probably lower. Putting a high/low digital outdoor thermometer near your citrus trees, and comparing it to the morning reading on your house-mounted thermometer may raise more goosebumps on your arms. At our place, it is not uncommon to see a six or seven degree lower temperature at 7 a.m. next to our citrus, despite the fact that the nearest Meyer lemon tree is only 20 feet away from the house. Get yourself one of those thermometers and check the readings in your own yard on these shivering mornings. That thermometer on the side of the house might say 33 degrees...but the one out at your frost-sensitive plants might say 27, enough to turn the insides of your lemons to mush.

Frost Cloths Protecting Lemons, Mandarins, Oranges

Several days before an expected frost (temperatures dipping down to 32 degrees) is the time to gather the necessary implements to protect your citrus trees, including giving the ground beneath them a good soaking (moist soil is better than dry soil at moderating the temperature beneath the tree).

Most gardeners first thoughts about protecting their citrus trees during a frost or freeze is, "protect the fruit!"

Four Winds Growers, the Winters-based wholesale grower of many excellent varieties of citrus, offers the Citrus Variety Information Chart at their website,

Included in that chart is extensive information about each citrus variety, including suitability for indoor growing; its bloom and fruiting seasons; its recommended summer heat level to produce good fruit; and, its minimum tolerable temperature for preservation of fruit quality.

  The chart points out that lemons, limes and citrons are most sensitive to frost, while sweet oranges, grapefruit, tangerines and calamondins are intermediate. Kumquats and Owari Satsuma Mandarins are the most frost-tolerant, braving temperatures into the twenties (that would classify as a freeze).

From that chart, here are the temperatures (in degrees Fahrenheit) at which citrus fruit damage may occur. 

Sweet Oranges
Washington Navel Orange  28
Trovita Orange  28
Cara Cara (Pink) Navel Orange 28
Lane Late Navel Orange  28
Robertson Navel Orange  28
Shamouti Orange (Jaffa Palestine)  28
Valencia Orange  28
Midknight Valencia Orange  28  

Blood Oranges
Moro Blood Orange  28
Sanquinelli Blood Orange  28
Tarocco Blood Orange  28
Sour Oranges
Bouquet De Fleurs Sour Orange  28
Chinotto Sour Orange (Myrtle-Leaf)  28
Seville Sour Orange  28
Bergamot Sour Orange  32
Gold Nugget Mandarin (Patented)  26
Tango Mandarin (Patented)  32
Owari Satsuma Mandarin  24
Dancy Tangerine  32
Clementine Mandarin (Algerian)  28
Murcott Mandarin  32
California Honey Mandarin  32
W. Murcott Mandarin  32
Kinnow Mandarin  32
Kara Mandarin  32
Page Mandarin  32
Piie Mandarin  32
Kishu Mandarin  32
Improved Meyer Lemon  32
Eureka Lemon  32
Lisbon Lemon  32
Ponderosa Lemon  32
Variegated Pink Lemon  32
Yen Ben Lemon  32  

Mediterranean Lemons
Villafranca Lemon  32
Genoa Lemon (Gea)  32
Limonero Fino Lemon  32
Millsweet Acidless Limetta  32
Marrakech Limetta  32
Bearss Seedless Lime (TahitiPersian)  30
Kaffir Lime (KiefferThaiWild)  32
Meican Lime (Key)  32
Thornless Meican Lime  32
Meican Sweet Lime  30
Palestine Sweet Lime  30
Rangpur Lime  32
Oroblanco Grapefruit  32
Rio Red Grapefruit  28
Star Ruby Grapefruit  28
Chandler Pummelo  28
Cocktail Grapefruit  28
Chinese Grapefruit  28
Melogold Grapefruit  28
Meiwa Kumquat  28
Nagami Kumquat  24
Indio Mandarinquat  26
Centennial Variegated Kumquat  30
Nordmann Seedless Nagami Kumquat  28
Marumi Kumquat  26
Eustis Limequat  32
Buddha's Hand  Fingered Citron  32
Etrog Citron (Ethrog)  32
Other Interesting Varieties
Minneola Tangelo  28   
Australian Finger Lime  32   
Yuzu  24   
Calamondin  32  
Variegated Calamondin  32

But what about the overall health of the citrus tree? How low can temperatures go during a freeze event before the tree is toast? 

 "I consider 22 degrees to be terminal for citrus tree cambium cells," says Cedar Seeger of Four Winds Growers. The cambium layer is the growing part of the tree, the cells that are producing new wood and healing wounds. It is located just beneath the bark.

And that's for a citrus tree in tip-top shape: good health, with moist soil around it during a freeze. Cedar uses the example of a Meyer lemon tree:

Blanket + Tomato Cage for Citrus Protection
"We often have a two to three hour dip to 28 degrees after storms; and if the above conditions are met, even Meyer lemon trees can survive, albeit not to happily, without protection. 28 degrees for four hours probably won't kill the tree, provided the rootstock cambium doesn't freeze. It will defoliate and lose twigs. At 24 degrees things start to get dicey. That's when the blanket, frost cloth, bonnet and/or the old-style, large outdoor Christmas lights that give off some heat will work wonders. Remember, those blankets and bonnets need to go to the ground in all cases."

Chandler Pummelo, Pummeled by 2010 Freeze

You may recall Thanksgiving Week of 2010, when morning low temperatures dipped well below freezing for six days in a row, led by a citrus-killing 27 degree morning on Thanksgiving.

When a large, cold-air mass moves in from the north after a storm in the winter, that is called an advective freeze. The one that sticks out in most gardeners' memories here was the freeze of mid-December 1990, when nighttime temperatures fell into the teens for several days in a row, with a couple of days that didn't climb above 32 degrees. To add even more injury, a second cold snap hit near the end of the month, with temperatures dipping into the mid-20's. Many of the most susceptible (frost intolerant) landscapes were completely lost; some nurseries never recovered.

"Our first year in the citrus business here in Winters was 1990-91. My wife, Mary Helen, and I have a Masters in Disaster," says Cedar Seeger. 

Which is why Cedar is an adherent of watching the dew point, the temperature at which saturation has been reached, when water vapor condenses into water. The lower the dew point, the more danger of cold damage to your plants. One good online source for dew point temperatures is the National Weather Service's Tabular Forecast Page  , which offers a forecast for two days in advance (that link is for Sacramento). 

"A good watering going into an advection night is mandatory. If the ground and surrounding grass is wet, it creates a micro dew point environment around the trees. In a dry, cold La Nina winter such as we're about to get, it is important to remember the dew point concept. At 22 and below, it's full on emergency response, pile straw, hay around trunks, anything, lights, covering," says Cedar, a man who learned these lessons the hard way.  But he is not an adherent of running sprinklers during a freeze.

"My experience with overhead sprinklers is that they more often than not freeze up, and then it's all over. And you are risking branch breakage on that ice-entombed citrus. Yeah, it can work, but screw it; it's messy, risky and a lot of work. Use the large Christmas lights and mid-weight frost covers. But pay attention to the trunk / rootstock. If that freezes, it's a goner."

Citrus trees most at risk to fatal damage from a frost or freeze are the young trees. It is vital that they be covered completely when a heavy frost or freeze is predicted, and provide protection for the trunk, bud union and rootstock area. That can include trunk wraps, newspapers, old carpeting. If possible, move small containerized citrus closer to the house, preferably next to a south or west-facing wall to maximize reflected heat.

In the book, "All About Citrus and Subtropical Fruits", author and grower Lance Walheim also suggests applying a copper-based fungicide to the trunk and then mounding or banking soil against the trunk and lower limbs. Just don't leave it on too long; fungal rots can develop (that copper can only work for a limited time). He advises leaving that soil next to the trunk from Thanksgiving until February, or March, in colder areas.

Don't be fooled by the predictions of a warmer and wetter El Nino winter. Mornings can still get too chilly for unprotected citrus. Welcome to Turkey Weather season!

Friday, April 17, 2015

Pruning Tomatoes: Don't You Have Anything Better To Do?

Once again, two tomato care questions have reappeared here: "Should I prune off  (snip off, pinch out) the first tomato flowers that appear, in order to get more tomatoes later?" And, "Do I need to prune my tomato plants?"

Those early tomato flowers, especially if the weather doesn’t cooperate, will fall all by themselves, thank you. Your assistance is not needed. And if you want to prune your tomato plant, you better have a damn good reason.

Flower drop and tomato fruit set failure can happen in May and June for a number of reasons, including night temperatures below 55; daytime temperatures above 90; excess nitrogen fertilizer, too much shade, too much smog, plants set out too early in spring, or planting the wrong variety for your area (Beefsteaks and San Francisco is not a match made in heaven).

However, by removing those flowers once they are in a situation where they can be pollinated successfully, what is accomplished by removing those flowers? FEWER TOMATOES! And, unless you are trying to stop production, it would be counterproductive to your ultimate goal: shoving that beautiful red orb into the face of your non-gardening neighbor in July, singing, “Nyah, nyah, nyah!”
Wow, where did this fallacy begin? One caller to the radio show offered a clue when he prefaced that question with, “Last night, the local TV Weatherman said…”

Bad move, taking gardening advice from a person who guesses for a living.

Still, that piece of  poor advice must have some historic legs to it. And sure enough, there are many people at Internet gardening forums who are passing on this wrong-headed notion. And as far as I can tell, it’s the result of one gardener reading a piece of university-based research on tomato pruning, and mangling the retelling of that research.

For example, Texas A and M University offers these tips for tomatoes:

"Greenhouse/Hydroponic Tomato Culture (winter)
Single crop rotation-seeded in July or by early August.  Transplants set in greenhouse within 10 to 30 days of seeding.  Harvest begins from 85 to 100 days following date of seeding and continues into June or early July.  Cessation of pollination is six weeks before  termination of the crop.  Growing point is allowed to grow for at least five to seven leaves  above last fruit truss to help prevent sunburned fruit.  Remove flower buds above last fruit truss to assure no additional fruit set."

Gardener A reads this, and then retells the story to Gardener B, omitting the fact that these were WINTER tomatoes grown in a GREENHOUSE, HYDROPONICALLY. Gardener B then tells Gardener C: “Pruning tomato flower buds is recommended by Texas A and M.” Gardener C then goes online and writes: “Remove flower buds on tomato plants to increase the number of tomatoes.”

Or something like that. And another digital gardening virus is born.


Cornell University says hacking back your tomato plants is not necessary:

“…you can grow perfectly fine fruit without pruning your plants. But if you want to prune, here are a few guidelines. For determinate types, there is no need to prune at all. For indeterminate types, allow one, two, or three suckers to grow from the base of the plant. Each of these will become a main stem with lots of flowers and fruit. Prune off all the others suckers and provide the plants with strong support. 

Research has shown that the best time to remove suckers is when they are about 3 to 4 inches long. For the semi-determinate types, limit your pruning. When the plant is 8 - 10 inches high, look carefully and observe the first flower cluster on the stem. Remove all the suckers below the flower cluster except for the one immediately below the cluster. You may have to go back and give these a second pruning 7 to 10 days later. Remove no more than that or you run the risk of pruning too much. The amount of pruning among these varieties to produce optimum yields varies. Some varieties would do better if you left 2 suckers below the flower cluster. Experiment and see which works best for the variety you are growing.”

The book, “Ortho’s All About Tomatoes”, puts it more succinctly, quoting the late Dr. Phillip Minges of Cornell: “Tomato yields per plant may be lowered by pruning. Removing the leaves or shoots does not conserve food for the crop, it tends to reduce the total food supply…use training methods that require little pruning.”

When and how should you prune tomatoes?
Very little, only when necessary, to keep the plants within bounds. If you grow your tomatoes in cages (recommended), you would only need to remove those branches that escape and are threatening to wrap itself around a nearby pepper plant.

If you grow your tomatoes using stakes for support, you may need to reach for your garden pruners, according to the University of California:
“Staked tomato plants usually require pruning to a few main stems. At the junction of each leaf and the first main stem, a new shoot will develop. Choose one to three of these shoots, normally at the first and second leaf-stem junction, for the additional main stems. Once a week, pinch off most of the other shoots, called suckers, with your fingers, to keep the plants from becoming to large for their support.”

And, it should be pointed out, that if you follow those pruning guidelines for staked tomatoes, you are sacrificing about 25% of your eventual tomato crop.

 That is yet another good argument to cage, not stake your tomatoes.

Cages can be made from sheets or rolls of concrete reinforcement wire with a six inch mesh (the six inch opening makes it easier to reach those tomatoes). The sheets are usually 42” by 84”. Snip off the vertical bars on one of the 42” ends, bend it into a circle, attach the horizontal arms from the snipped end around the other  42” side and you have a tomato cage that’s 42” tall and about 27” in diameter. And it will last for decades. Want a bigger cage? Turn the sheet sideways, snip one of the long ends, bend it into a circle, and you have a cage that’s 84 inches tall and about a foot wide. But I would only do that if I am trying to grow tomatoes as per the instructions of a square foot garden.

And if you need another reason NOT to prune your tomato plants, there's this:
Sunscald (sunburn) of tomatoes. The fruit turns light brown and leathery on the side exposed to the sun. The solution? Don't prune the leaf cover from the plant!

A final hint when searching for garden answers on the Internet. Be leery of advice from gardening forums, unless that advice is linked to a study or research that you can also access. When using a search engine, include the words to identify a prominent agricultural school where the advice is reviewed by multiple parties before publication: UC (University of California), WSU (Washington State), Cornell, TAMU (Texas and M), etc.
For example Googling the phrase “tomato worm UC” will lead you to the University of California Integrated Pest Management website first. If you were to just enter the words, “tomato worm”, well…good luck.

Tuesday, March 31, 2015

Foliar Feeding: The Pros and Cons

  You know how it is: you hear something enough, you believe it's true. Look on the side of any box of water soluble fertilizer, or any organic gardening guide, and there will be instructions on foliar feeding: spraying a water soluble fertilizer onto the leaves of a plant, as an alternative source of nutrition for the plant.

      Awhile back on the radio show, a tempest in a teapot developed when Milo Shammas, the President of the Dr. Earth line of organic products, mentioned that the best way to apply a foliar fertilizer, which he endorses, is in as fine a spray as possible. In his corner, Rodale's Encyclopedia of Organic Gardening, which states: "Plants can absorb liquid fertilizers through both their roots and through their leaf pores. Foliar feeding can supply nutrients when they are lacking or unavailable in the soil, or when roots are stressed. It is especially effective for giving fast growing plants like vegetables an extra boost during the growing season...Any sprayer or mister will work, from hand trigger units to knapsack sprayers. Set your sprayer to emit as fine a spray as possible."

      Disagreeing with the "fine spray" approach is another organic advocate and frequent guest of the radio shows, Steve Zien of the Sacramento area-based organic consulting service, Living Resources Company
     Zien says, "Some time ago I read a few studies that indicated that most of that (spraying with a fine spray) was not necessary. The studies used radio isotopes to follow the nutrients in the foliar fertilizer. They found that it got into the plant even when the water droplets were large. Another study indicated that even with the best spray equipment making the smallest water droplets possible with today's technology, the water droplets were still too large to physically enter the plant. They concluded that water droplet size is not important when foliar feeding. Other studies have shown that foliar fertilizer can even be absorbed by branches and tree trunks.  These two facts indicate that where you spray is also not critical.  Numerous studies have shown that foliar feeding is much more efficient at getting the nutrients absorbed and to the entire plant and more rapidly as well. 
     I think all the studies emphasize that even with all the benefits of foliar feeding, it cannot be considered a substitute for proper soil nutrition, and I fully agree with that. You need to feed the soil foodweb for healthy, pest resistant plants.I no longer worry about where I apply the foliar fertilizer. I try to apply it to as many plant surfaces as possible but do not worry about paying attention to the undersides of the leaves."

     Throwing cold water on both those practices are a couple of college educators, Deborah Flower of the Horticulture Department of American River College in Sacramento; and, Linda Chalker-Scott of the Horticulture Department at Washington State University and author of the award-winning book, "The Informed Gardener", who says this about foliar feeding: 
     "The existing research does not justify foliar fertilization of landscape plants as a general method of mineral nutrition. It can be useful for diagnosing deficiencies; for instance, spraying leaves with iron chelate can help determine if interveinal chlorosis is from iron deficiency. It would obviously have a benefit for those landowners with landscape fruit trees that perpetually have flower or fruit disorders associated with micronutrient deficiencies. Applying fertilizers to leaves (or the soil) without regard to actual mineral needs wastes time and money, can injure plant roots and soil organisms, and contributes to the increasing problem of environmental pollution. The bottom line:
• Tree and shrub species differ dramatically in their ability to absorb foliar fertilizers.
• Proper plant selection relative to soil type is crucial to appropriate mineral nutrition.
• Foliar spraying is best accomplished on overcast, cool days to reduce leaf burn.
• In landscape plants, foliar spraying can test for nutrient deficiencies, but not solve them.
• Micronutrients are the only minerals that are effectively applied through foliar application.
• Foliar application will not alleviate mineral deficiencies in roots or subsequent crown growth.
• Foliar spraying is only a temporary solution to the larger problem of soil nutrient availability.
• Minerals (especially micronutrients) applied in amounts that exceed a plant’s needs can injure or kill the plant and contribute to environmental pollution.
• Any benefit from foliar spraying of landscape trees and shrubs is minor considering the cost and labor required."

     Chiming in is Deborah Flower of American River College: "I have been reading 'Plant Physiology' by Taiz and Zeiger, and 'Mineral Nutrition of Higher Plants' by Horst Marschner.  The latter discusses foliar feeding in chapter 4.  It says: there are small pores in the cuticle through which minerals can enter the plant.  These pores are in highest density near guard cells around stomata and at base of trichomes (hairs, scales, etc.).  They are tiny and lined with negative charges.  So, only very small (less than one nanometer in diameter) cations and uncharged molecules will enter these openings.
It says leaves do absorb ions, but (pages 123-125):
Rate of uptake is VERY low.
Rate of uptake varies between species and growing conditions.  Plants with thicker cuticle (due to species or growing conditions) absorb less.
Older leaves have lowest rate of uptake due to leaky plant cells that fill intercellular spaces, which is where ions travel in the leaf.
A very high concentration of ions is needed outside the leaf to get any into the leaf.
The supply of nutrients in the leaf from foliar feeding is temporary.
There is limited movement of nutrients from leaves to other plant parts.
Urea can enter leaves through these openings (ammonia and nitrate cannot), because it is an uncharged particle, but can cause damage in the leaf, due to nutrient imbalance in the leaf once it is absorbed.
Surfactants should be used with all foliar feeding to increase surface spread of spray.

      So, my opinion is that yes, plants do absorb nutrients through their leaves (neither book mentioned absorbtion through branches or trunks) but the amount is very small, nutrients do not travel far from point of entry, and there is lots of nutrient run-off during the process, which can lead to pollution.  Therefore, foliar feeding is not effective as the primary source of nutrients for plants. I disagree that foliar feeding gets nutrients to all parts of the plant. There is lots of evidence that fertilizer that gets into the leaf migrates little to other parts of the plant. It stays in the leaf or travels to a strong sink like a fruit.  Foliar feeding can correct micro-nutrient deficiencies in leaves and some fruit, but until the nutrition is balanced in the root zone, the symptom will continue to appear in new plant parts. Many of my students seem to believe foliar feeding is better for the plant than nutrient absorption by roots, and that concerns me.  Foliar feeding can be used to correct some nutritional problems, primarily in production situations, but should not be relied on as the primary source of nutrients for the plant. If people are foliar feeding I believe most of the nutrients being absorbed by the plant are entering the roots, probably after running off the plant onto the soil."

  Milo Shammas, of Dr. Earth, responds: "Fred, all very true and I agree with her, I do not recommend foliar feeding as the primary source of nutrients. Whatever runs off the foliage will ultimately be absorbed by the root system. Nothing can replace ion absorption through the root system.
 Foliar feeding as a supplement? Yes
Is it effective? Yes
Would I depend on it solely? No
Is there harm in using it? No
Do younger leaves absorb it better? Yes
 I own and manage 45 acres of organic walnuts and I personally spray my ranch with Dr. Earth liquid solution twice a year,  I do spend the money on it, I have conducted the efficacy and I know it works, I do believe in it, I do endorse it, I do not depend on it."

    After standing back, listening to all this, I have come to the conclusion: although foliar feeding may have minimal value, it does have a bigger, positive effect: washing off bad bugs from the leaves. Of course, a spray of water can accomplish the same thing.