Saturday, September 29, 2012

You Can't Grow That!

Following are the highlights of a presentation I gave today for the University of Tennessee Gardens Fall Symposium. The theme of the symposium this year was "Incredible Edibles."
“You can’t grow that!” is the reaction I often get when I suggest to one of my gardening friends that I plan to try such-and-such next season. However, every time I look for information on a food crop that supposedly does not grow in Zone 7, I find plenty of suggestions and advice from gardeners who have done just that. In a minute, I will cite some examples of tropical and sub-tropical food plants that you certainly can grow.
I was appalled by an article I read recently that suggested producing the majority of our food locally is an impossible dream. I wonder how the Native Americans who occupied this Valley centuries before Europeans arrived would have reacted to that remark? Many of them were farmers as well as hunter-gatherers, and this region of the world is unusually lucky in having an abundance of edible wild plants. I have several examples of those to share with you today, also.
A third group of food plants includes some that lots of people apparently grow, but for some reason you never hear much about. I will offer two examples from this group.
First, however, let’s look at some plants you “can’t” grow here.

Tropical and Sub-tropical Plants:


Plants grown in large containers outside during the warm months will produce fruit. Dwarf and super-dwarf cultivars are available in the nursery trade. The one pictured, ‘Novak,’ fruits at only 4 feet tall.
The growing medium must be well-drained. Bananas do not tolerate wet feet. Fertilization with a balanced formula monthly is necessary. Bananas need about 1 ¼ ounces of nitrogen per month when young, and double that amount when mature. If your fertilizer is 8 percent nitrogen, that is, the NPK numbers are 8-x-x, you should apply a pound of this fertilizer around the base of the plant monthly, gradually increasing the application to two pounds over the course of the season. If the temperature at night is below 50°F, as during overwintering in a garage perhaps, don’t fertilize.
While bananas are generally tolerant of cold down to 28°F, they perform best when grown under constantly warm to cool conditions. If winter storage is a problem, however, you can take several steps to keep your banana plants growing. First, if you have a suitable sheltered spot exposed to southern sun, you can probably overwinter a banana plant outdoors as far north as Zone 4. This is accomplished by cutting it down, covering the base with a bushel basket, and piling leaves on top to protect the underground stem . Do this as soon as frost kills most of the top growth. Check such plants frequently in early spring and remove the covering as soon as shoots emerge. Be ready with a frost blanket in case of a late cold snap. A more reliable way of overwintering is to dig up small shoots and pot them in containers as houseplants for the winter. Grow in a bright, warm location and fertilize lightly until you are ready to move them outside again. Generally, you allow only two shoots to develop. The older one will fruit and the other will provide the subsequent crop.

Bay Laurel

This frost-tender shrub or small tree prefers rich, organic, well-drained soil. It grows best as a container plant, in full sun to partial shade. Do not allow plants to dry out, but do not allow soil to become soggy.  Use a growing medium intended for citrus, if available. Can be successfully overwintered in Knoxville if grown in a sheltered location and the soil is prevented from freezing by deep mulch, an adjacent building foundation, or a water feature.


The photo is my Meyer lemon ‘Improved’ on a dwarf rootstock. This is a hardy citrus that will tolerate cold down to 34 degrees F. Kumquats, such as ‘Meiwa,’ can take it down in the 20s. The vast number of selections of grafted citrus means you must pay attention to rootstock and graft alike. Citrus prefers a gritty, well-drained growing mix and plenty of water and fertilizer when young. Drought tolerant as they get older. Water citrus when the top one inch of growing mix feels dry when you stick your finger into the soil. Feed once when the plants move outdoors, and again about three months later, using a good, balanced organic fertilizer. Formulas made just for citrus are recommended and available from garden centers or by mail order. Glossy, dark green leaves indicate that the plant is receiving adequate nutrition. When in doubt, err on the side of less food and less water. Too much of either one will result in leggy, unsightly growth and poor fruit production.
In the second year after transplanting nursery stock, you should expect a few fruits. Thereafter, fruit production will increase with the size of the tree. Lemons and limes can bear almost at any time of year, but most other varieties bear the best crop after their spring bloom. Leaving the fruit on the tree until you are ready to eat it is the best bet, as the fruit becomes larger and flavor improves with time. Don’t wait until the fruit begins to dry out, however, before picking. Among the numerous varieties of citrus available, consider one or more of the following. Meyer lemon is a small form with smooth, thin-skinned fruit and reasonable cold tolerance. Kumquats have good cold tolerance and adapt well to containers. Selections include ‘Nagami’ and ‘Meiwa,’ both of which bear during fall and winter. Mandarin oranges and tangerines also exhibit good cold tolerance, but with some varieties, such as the Clementine tangerine, you need two plants for successful pollination. Varieties to try include Satsuma, Owari, Clementine, Dancy and Changsha tangerines, and Minneola and Orlando tangelos.


Figs have been grown for centuries, and can be over-wintered outdoors in Knoxville in a sheltered spot. ‘Brown Turkey,’ ‘Celeste’ and ‘Chicago’ are popular cold-tolerant cultivars. Grow in any reasonable soil in a spot sheltered from winter winds. Keep root suckers pruned off and head back the tree to maintain shape. All are considered easy to grow, with water management being a more important consideration than soil fertility. Poorly drained, constantly wet soil will rot the roots, but trees should not dry out to the point that leaves begin to wilt. Since the tree should be sited in as much sun as possible, water needs during hot weather can be significant.
Purchase nursery-grown stock of a known cultivar, or root a cutting from a tree of known provenance. Cuttings taken in August will root readily and can be transferred to their permanent location the following year. Plant the tree a little deeper than it was growing in the nursery container, using a well-drained mix such as has been previously recommended for growing avocado and citrus. Add a little bone meal to the mix at planting time. Figs are not heavy feeders and phosphorus is more important for them than nitrogen. You will need a container holding fifteen to twenty gallons of potting mix to accommodate a mature fig tree. Trees can be kept in bounds by thinning the main stems and by root pruning every three years.
Overwintering a container fig is relatively easy. When leaves fall, move the tree indoors to a cool spot. Light is unnecessary while the tree is dormant, so even a closet will do. Water about once a month. As the weather begins to warm up, gradually acclimate the tree to outdoor conditions, and new buds should begin to swell. Thereafter, resume your normal schedule of watering. Work a few tablespoons of bone meal into the top layer of soil when the plants are growing well again.
A fig tree planted in the ground in a sheltered spot can be successfully overwintered if the roots are protected from freezing. When dormant, the tree can be wrapped in a frost blanket until warm weather returns. Gardeners as far north as Zone 5 report success with this technique. Some drape the tree with Christmas lights connected to a timer, thus providing extra warmth on cold nights.


Olives typically do not do well in the humid South, but the Spanish Arbequina cultivar does perform well here. I saw olives fruiting in small pots at the Farmers Market this summer. They are decorative plants that adapt well to container culture. Use a well-drained mix, such as intended for citrus or palms, and keep well-watered and fertilized during the growing season. Hold back on water during the winter, but do not allow to dry out completely, and keep the plant in a sunny window.

Unusual ornamental edibles:


Tolerant of poor soils, drought and shade, the native elderberry is a reliable and easy edible shrub. Two plants are needed for pollination, except in the cultivated varieties ‘Nova’ and ‘York.’ European elderberry is also available; ‘Black Lace’ is a particularly decorative selection.


This Native American tree is under-appreciated. Usually found in rich, moist, organic soil near rivers and streams. Once established, the trees are rarely bothered by pests or disease. Selections available in the trade. Choose two different varieties to insure pollination.  The tree is the host plant for the zebra swallowtail butterfly, and chilled pawpaw is said to have been George Washington’s favorite dessert.


A sturdy native American tree, persimmon is self-fertile. Several cultivated varieties are available, along with a hybrid between the American and Asian persimmon species. Attractive checked bark and fruits remaining after leaf fall create year round interest in the landscape. Tolerates a wide variety of conditions, but prefers rich, well-drained soil high in organic matter.

Prickly Pear

Native to the desert Southwest, but naturalized in some places around here, this cactus can grow to an impressive size, provided it has plenty of sun and well-drained soil. Handle with extreme care. Tiny spines come loose and work themselves into your skin if touched. Fruits are used for juice, jam and wine-making. Leaf pads are de-spined and eaten as a vegetable, nopalitos, available canned in the Latin section of the grocery store.
A fruiting tree with four season interest: spring flowers, summer fruits, fall foliage and winter bark and buds. Fall foliage color is often spectacular. Numerous cultivares are widely available, and tolerant of just about anything but wet feet.


Often called “bear grass” this desert native is naturalized throughout the Southeast. Flowers are edible raw or in stir fries and omelets. (Some people may have a reaction, but this is rare. Eat only one flower the first time.) Trim out the centers and chop them separately, using the petals whole.

Completely Unexpected:


You can easily produce a year’s supply from a couple of purchased roots. Look for those with attached green stems, and use the best-looking ones to start your plants. Select a container at least four times larger than the piece of rhizome you are planting. A 12 to 14 inch azalea pot works well. This will allow for the development of an extensive root system. Fill the container three quarters full with a good, well-drained potting mix containing plenty of compost. Place the rhizome on top of the mix with the eyes pointing upward. Cover with more potting mix and water well. Place the container in a plastic bag in indirect light until green shoots appear. (This can take a month.) Then remove the bag and water well. Keep the plant in bright, indirect light and never allow the soil to dry out. Growing plants need protection from wind and should be brought indoors any time the temperature is headed below 50°F. The ideal growing temperature is 75°F to 85°F. Water and feed regularly, like most houseplants.


Saffron crocus grows like any other crocus, but blooms in fall, not spring. It grows well in Zones 6 through 9, and prefers good, well-drained soil in full sun. A patch of ten square feet, enough to accommodate about 50 bulbs, will provide an increasing abundance of spice as the plants mature and multiply. Set them out in summer, while they are dormant, six inches apart and three inches deep. Drainage is essential. Avoid keeping the soil too wet when the plants are dormant. You can overplant, if you wish, with annuals, but take care not to irrigate too much. Pull up the annuals when you see the new green shoots of saffron poking through the soil in autumn. When the lovely lavender-blue flowers open a few weeks later, harvest by picking the bright red stigmas by hand. You can use them immediately in such Mediterranean dishes as paella, bouillabaisse, and risotto, or dry them for a few days before storing in an airtight container for later use.
With just a little planning, your yard can become more beautiful and productive. Just be sure not to listen to anyone who says, “You can’t grow that!”

Friday, September 21, 2012

Happy Autumn Equinox!

Tomorrow, September 22, is the Autumn Equinox, and the weather has mercifully cooled down a bit. The accompanying photo depicts one of our favorite native plants for this season, smooth aster (Aster laevis). This is a cultivated variety named ‘Bluebird.’ Besides adding color, it attracts butterflies and bees.

For the backyard gardener, this time of year can be as busy as spring. Besides cleaning up spent plants and dealing with late summer’s abundance, you must also focus attention on the cool weather crops appropriate for the Tennessee Valley's “second spring.” From now until around Thanksgiving, you should be able to produce many of the same crops you’d grow in February, March and April.

Fast-maturing peas can be planted now, and you can transplant broccoli, cabbage and their relatives. If you did not start your own plants, you can easily find them at garden centers. Nurseries have responded to the surge in home food gardening by offering an increasingly good selection of transplants for fall planting. I have previously mentioned that late summer is also a good time for planting carrots, beets, leeks and turnips. There is still time to get them in the ground.

Greens Crops
We received over five inches of rain earlier this week, and our first planting of lettuce responded with rapid growth. We are starting more lettuce seeds in small pots tomorrow.

Deer Tongue – This is a loosehead heirloom from Southern Exposure Seed Exchange. It did not do so well for uslast spring, so we are giving it a try as a fall crop.

Ashley – A frilly loosehead type with pink coloration on the leaves, it has performed well in the past as a fall and winter crop.

Lollo Rossa – A crinkly, deeply savoyed loosehead with dark red markings on the leaves, this one also has a delicious, succulent texture.

Spinach provides healthy greens all winter, so we will plant about 25 square feet of it. ‘Bloomsdale’ is the best variety we have tried, and is the one most widely grown in this area. You can pick individual leaves and keep harvesting one planting for months. Two other green crops to sow this week are arugula and corn salad. Both can be sown in succession every two weeks from now until the end of October. The Asian mustards, tatsoi and mizuna, offer additional options for fall planting, but we like to wait to plant them until the weather is really crisp, to minimize insect problems.

We will also sow chervil, which grows happily for us throughout the winter months, and here and there some cilantro seeds.

Preserving Summer Abundance
Besides all the garden chores, fall brings with it the need to preserve summer’s abundance. Many gardeners have piles of tomatoes, peppers and cucumbers at this time of year. Did you know that you can freeze tomato-based foods like salsa and gazpacho? In recipes where the vegetables are chopped, texture is less of an issue, so freezing is an option. Also, the acid from tomatoes and citrus juices helps to preserve the summer-fresh flavors for a mid-winter treat.

A food processor will facilitate making either of these recipes, but you can also chop everything by hand. These recipes also lend themselves to the use of heirloom tomatoes, which may not give good results when canned. I developed the gazpacho recipe by experiment, and it subsequently occurred to me that salsa would work, too. I use 2-cup rigid plastic containers with wide mouth screw tops for freezing both these products. Either recipe can be easily multiplied. If you don’t own a kitchen scale, use the equivalent volume measures for the gazpacho base. As long as the ratios are maintained, the flavor will be great.

Frozen Salsa

1 cup chopped white onion
1 quart cored and chopped firm ripe tomatoes
1 cup chopped green or red bell peppers
¼ cup chopped seeded hot peppers, more or less, depending upon desired heat level
2 cloves garlic, minced
½ cup loosely packed chopped cilantro leaves and tender stems
juice of two lemons or three limes
 teaspoons salt

Place the onion in a heatproof strainer in the sink and pour 2-3 cups of boiling water over it. This step prevents the onion from becoming too strong during storage.

Combine the onion with the other ingredients and mix well. Chill until cold. Fill freezer containers to the mark, seal, label and freeze. To use, thaw overnight in the refrigerator and serve with chips.

Freezer Gazpacho Base

8 ounces ripe tomatoes, seeded and chopped
4 ounces cucumber, seeded and chopped
2 ounces bell pepper, seeded and chopped
¾ ounce red onion, minced
¼ ounce garlic, minced
1 ounce fresh mixed herbs, minced (basil, chervil, chives, parsley, tarragon)
A few grinds of freshly ground black pepper.
¼ teaspoon coarse sea salt
½ teaspoon sweet paprika
1 tablespoon freshly squeezed lemon juice
2 tablespoons extra-virgin olive oil

Combine these ingredients in a large bowl and mix well. Chill until cold. Fill freezer containers to the mark, seal, label and freeze. To use, thaw overnight in the refrigerator. Combine the gazpacho base with enough tomato juice, chicken broth or a combination to achieve a consistency you like. Serve chilled, garnished with sour cream, croutons, and finely chopped fresh parsley.

Friday, September 14, 2012

Pepper Season Is Here!

The tomatoes, with the exception of our late planting of Marglobe, are starting to wind down. We will pull all the spent vines this weekend, having already replaced the Bush Big Boy plants with fall lettuces.

Peppers, however, are anything but tired, and seem intent on supplying us with more than we can use for weeks to come. We have several varieties that have given great results this season.

California Wonder
We have been growing this one for years. If we could grow only one pepper, it would be this one. Large, uniform fruits ripen to bright red and are perfect for stuffing, relish or any recipe calling for sweet peppers. From four plants we can pick half a dozen fruits every few days.

Long Sweet Pepper
This old-fashioned type of pepper is easy to grow, versatile in the kitchen and prolific. Two plants are yielding one or two fruits every day. This variety is not as sweet as a bell pepper, but it is more likely to give a good harvest under less than perfect conditions. Often called a “frying” pepper, it stands up well to either pan frying or roasting.

Fish Pepper
If you like heat, you always want to include a small hot pepper variety in the garden. This one, originally from Thailand, came from Southern Exposure Seed Exchange. The variegated foliage is decorative, and the fruits start out green-and-white striped, ripening through yellow to orange-red. They are quite hot and ideal for spicing up relish, for red pepper vinegar (see below) or for garnishing Thai or Southwestern dishes.

Ashe County Pimento
This one looks like a flattened bell pepper, with thick, deep red flesh when ripe. It is the ideal pickling pepper, and can be used at any stage of ripeness. We will grow this one again next year, just for making relish. Seed also came from Southern Exposure.

This is the standard, long, red, hot-as-hell pepper that is dried and ground to produce the familiar powdered heat. I find they dry perfectly spread out on a tray at room temperature. When they are leathery, transfer them to a jar and place a couple of silica gel packets in with them to prevent mold. They will keep for a year.

Here is a recipe for red pepper vinegar. It can be made with any variety of hot pepper you happen to have. When working with hot peppers, always take care not to get the juice in your eyes. Wear plastic gloves, or simply avoid touching your face until you have washed your hands with plenty of hot, soapy water.

This recipe can be easily multiplied if you have a bumper crop of hot peppers.

Red Pepper Vinegar
Weigh out four ounces of whole, unblemished hot peppers. Wash them and pat dry with a kitchen towel. Cut a small slit near the stem end of each pepper with a paring knife. This allows the liquid to enter the pepper and keeps them from floating in the jar. Place the peppers in a clean, sterilized, canning jar. In a saucepan, bring 1 cup of white vinegar and 1-½ teaspoons of pickling salt to a boil. Carefully pour the steaming-hot  vinegar mixture over the peppers. Place a canning lid on the jar and allow to cool. Store in a cool, dark place for at least two weeks to extract the flavor. Refrigerate after opening.

Friday, September 7, 2012

Keep Your Garden Producing

We took last weekend off from writing in observance of Labor Day, but we spent a lot of time in the garden.  Now is a great time to take steps to maximize your food production for fall and winter.  Here are some tips to make your outdoor time pay off during the last weeks of summer.
Keep vegetables picked.
Beans, cucumbers, okra, peppers, squash and tomatoes will all bear better if you keep their fruits picked. (Yes, all these are fruits, botanically speaking.) Harvest beans when they are about the size of a pencil, and don’t let cucumbers get too fat. Pick okra when the pods are about three inches long, unless you are growing one of the varieties that remain tender when large. Pick peppers at whatever stage you prefer to use them, but don’t let ripe ones hang on the vines. Vine-ripened taste is why you grow tomatoes, but, again, don’t let mature ones remain on the vines. Besides impeding further production, overripe fruits attract insects and birds that will also damage unripened fruits.
Maintain vigilance for pests.
Bean leaf roller adult
The heat and humidity this time of year favor rapid insect multiplication. One or two bugs can turn into a horde overnight. Our late plantings of brassicas have been visited by both cabbage butterflies (Pieris rapae) and bean leaf rollers (Urbanus proteus). The latter also attacks brassicas, and metamorphoses into an attractive adult skipper that flits above our buddleia bushes, providing a good example of gardening yin and yang. See the photo at left. I enjoy the butterflies, but not their caterpillars. We killed 17 caterpillars in one bed and 47 in another one, despite weekly dustings with Bt. So far, we have kept the damage to a minimum, but all the transplants show at least a hole or two from munchers. The next sowing, around the middle of September, should produce plants that will go into the ground after cooler temperatures have solved the insect problem.
Another insect that can be controlled by hand is the ubiquitous squash bug (Anasa tristis). Its clusters of reddish-brown eggs [image] can be found on the undersides of the leaves of squash, pumpkins, melons and cucumbers. Larval squash bugs feed on the leaves and immature fruits of these crops. Adults [image] have sucking mouthparts and can do serious damage to squash, tomatoes and peppers by transmitting rot fungi. Squash bugs are prolific and require multiple control methods. Using a screen house to exclude them is one possibility. A simpler technique involves checking the leaves of the plants every few days and destroying any eggs you find. Sprays containing neem oil are moderately effective in repelling squash bugs.

Squash bug eggs

Squash bug
 Heat-stressed plants may attract tomato hornworms, or you may be growing moonflower vine (Ipomoea alba), night-scented tobacco (Nicotiana sylvestris, N. alata) or similar evening scented white blooms. All these attract sphinx moths (Sphingidae), the adults of hornworms. The caterpillars can devastate a tomato plant in short order, and grow to the size of your thumb or larger. Inspect your plants and pick off the smaller caterpillars before they do extensive damage.
Renovate planting beds.
Remove spent plantings and add soil amendments, such as compost or peat moss, to your growing beds. If you are going to use them for a fall or winter green crop, add nitrogen in the form of cottonseed or blood meal. Bone meal or a small amount of wood ashes should be added to beds intended for cool weather root crops, such as carrots, beets or turnips. Too much nitrogen reduces yields in these crops, making them good candidates to follow nitrogen-hungry vegetables such as corn, spinach or brassicas.
For beds that will not be used again until spring, this is the ideal time to add wood ashes or lime along with organic amendments like shredded autumn leaves or pine needles. After the winter freeze, these materials will break down, improving the soil’s structure, moisture holding capacity and fertility.
If the soil in a vacant bed is in good shape, plant a cover crop to be tilled in next spring. Fast growing cool season annuals like alfalfa and annual ryegrass are potential choices.
Preserve your harvest
The seasonal abundance in your backyard and at the farmer’s market creates plenty of opportunities to preserve food for the coming months. Freezing is the simplest way to preserve foods such as beans, okra, carrots and peppers. Softer foods, like tomatoes, retain their texture best if canned, although they can be frozen for soups and sauces. 
Trim green beans and carrots to the size you want them. These vegetables should be blanched three minutes in boiling water, then drained and refreshed in ice water before being packed into freezer containers.
Wipe okra pods with a dry kitchen towel and drop into freezer bags or boxes. If you want the okra sliced, do this after thawing. Peppers should be stemmed, seeded and cut into the size you desire. Spread them out on waxed paper on a cookie sheet and freeze overnight. Then transfer the frozen peppers to freezer containers.
Information on home canning can be found in lots of places. Make sure you follow instructions precisely to insure food safety. The best foods to can for beginners are tomatoes, tomato juice, peaches, and various pickles and relishes. These acid foods naturally resist bacterial spoilage.
 Jams, jellies, preserves and conserves all employ sugar to preserve the food. They can be sweet, like strawberry jam, or savory, like chutneys and herb jellies.
Herb Jelly
Prepare an extract of herb leaves by placing one cup (packed) herb leaves in a large heatproof bowl. Cover with 1 cup of boiling water and allow to steep for 10 minutes. Strain. For each cup of apple juice called for in your favorite apple jelly recipe, add two tablespoons of the herb extract. Then proceed with the recipe as directed. This works especially well with “sweet” herbs such as basil, lemon verbena and rosemary. You can adjust the amount of herb flavor to taste.
Check out our In The Kitchen page for an easy and delicious dill pickle recipe.