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!