Vegetable Garden Basics

With the mercury hovering around 25 degrees, my thoughts turn to the warmer days ahead. I am refining my garden plan for 2014. If you have not made a plan yet, now is the time, before spring chores eat up most of your gardening time. Your plan need not be elaborate, but it should at least cover three things:

1. What am I going to plant?
2. Where am I going to put everything?
3. What is the best strategy for succession planting? 

Food garden at UT Gardens

Here are some tips for answering these questions. One of the best ways to determine what to plant is to ask the other people in the family. You may think growing salsify would be fun, but your kids may want tomatoes or strawberries. Make a list and let everyone vote. If you are a novice at food gardening, limit yourself to three or four crops until you get the hang of growing those, then branch out. My top four choices are beans, lettuce, tomatoes and cucumbers. If I could grow only four vegetables, I would grow these, lettuce in spring and fall, and the others as summer crops.

Choosing a site for your vegetable garden can be the most critical decision you make, in terms of success or failure. Of primary importance is sunshine. Veggies need at least six hours of sun a day, and the more sun, the better. Don't locate your food garden in a low-lying spot where water stands for more than a few hours after a heavy rain. No vegetable likes wet feet, although they all need about an inch of water a week. Speaking of which, be sure you can reach your vegetable garden with a hose, or you will be toting water in buckets during high summer. Your soil should be well-drained, moisture retentive and organically rich. Work in composted organic matter in late winter, as soon as you can work the soil. For a small plot, you can buy compost, peat, or pine bark fines to work into the bed. I suggest adding 3 two-cubic-foot bags of this material per 100 square feet of growing bed, unless your soil is already in great shape. Add more each year, and in five years time you will have the best veggie beds on the block. Good soil is the key to great veggies.

Late winter is also a good time to incorporate organic fertilizers into your garden soil. Doing so gives the weather and beneficial bacteria a chance to decompose these materials into a form your plants can use. I add a cup of cottonseed meal per 10 square feet of growing space, along with a similar amount of bone meal and two tablespoons of pelletized dolomitic limestone. (I leave out the lime if I am growing potatoes.) These amendments are best added around the first of February, if you intend to begin planting in March. That allows a month for breakdown to begin. If you determine that plants need more nitrogen later on in the season, I suggest using a balanced organic fertilizer mix available commercially, rather than more slow-release amendments. When plants are really growing the nutrients will not be released fast enough.

I should also say that, although I prefer organic fertilization wherever possible, I see nothing wrong with using a soluble fertilizer, such as Miracle Gro(TM) in order to salvage a crop of veggies. Doing so is less likely to cause harm than allowing the plants to get stressed and attract insect pests.

Regarding succession planting, this is the key to growing a lot of food in a small space. The most important point to remember is that here in the Tennessee Valley, we have three growing seasons. Two cool ones in spring and fall, and a warm to hot season in summer. Once you have your veggie list in hand, divide it into cool season and warm season crops. The most popular warm season crops are beans, corn, cucumbers, okra, peppers, tomatoes and squash. Greens of all types are the easiest cool season crops, including arugula, lettuce, mustards and spinach. The cabbage family also needs cool temperatures, as do green onions and leeks. Plan on growing cool season crops from March 1 to June 1, warm season crops from June 1 to September 1, and cool season crops again around Labor Day. for the ones to be grown from transplants, either plan on purchasing them from a garden center (recommended for beginners) or start seeds about four to six weeks before you will need plants.

When your early crops of greens and scallions are done, remove plant debris and move in the summer crops. When these are up and growing well, fertilize. Start moving in the fall plants as the summer veggies start looking exhausted. Feed the fall crop when all the summer crops are gone and the fall plants are established. 

By following these simple guidelines, you should be able to grow enough food to eat, and perhaps have some extra to can or freeze this summer. 

Fall Gardening and Fertilizer Cost Calculations

More On Fall Crop Selection

Yesterday we transplanted our 30-day old starts of fall brassicas:

 Bak Choy, Baby Choy—a dwarf cultivar from the Burpee seed rack at Lowe’s

 Broccoli, Thompson—a variety developed specifically for fall culture, from Southern Exposure

Brussels Sprouts, Catskill—an old standby from the Burpee seed rack

 Cabbage, Early Flat Dutch—starts from a gardening friend

Cabbage, Savoy Perfection—also from Southern Exposure, recommended for fall growing

Chinese Cabbage, Michihili—the standard “napa” type, from Mayo Garden Seeds

We had previously transplanted cauliflower ‘Frosty’ from the same July 21 sowing, and those plants are now almost a foot tall. All of our brassicas receive a dusting of Dipel weekly. Today, I fed each transplant about two tablespoons of cottonseed meal, working it into the soil at the base of the plant.

We also started five Romaine lettuce cultivars:

·         Anuenue—developed for Hawaiian heat, our seeds came from Southern Exposure

·         Freckles—from the Burpee seed rack

·         Forellenschluss—also from Burpee

·         Jericho—originally from Israel, another one from Southern Exposure

·         Generic-- a green variety that grows well here, purchased from Mayo Garden Seeds

We expect these plants to be ready to go into the ground in three weeks. Romaine lettuces are more heat tolerant, and so will perform well despite the unusually warm early autumn days we are likely to experience.

A Note on Amy’s Sugar Gem

We purchased the seeds of this “patio” size tomato from Southern Exposure on the basis of their glowing catalog entry. We have not been disappointed. Besides abundant fruit production despite the unseasonably hot, humid summer, the plants have remained free of common problems. The fruits resist cracking, even with the boom-and-bust rainfall distribution we had this year. The flavor is superb, they keep a week or so after picking. If you are inclined to canning, Amy’s Sugar Gem is a cinch to peel after 30 seconds in a boiling water bath. Cut a tiny slit in the blossom end with a serrated knife, plop them in rapidly boiling water for no more than half a minute, and transfer to a sink full of cold water with a slotted spoon. After another half minute, the peels can be slipped off easily with your fingers, and the fruit will remain whole and undamaged.

Determining Fertilizer Costs

I covered this topic in The New American Homestead. Here is how to compare the cost of different brands and types of fertilizers. Nitrogen, phosphorus and potassium percentages by weight are printed on every fertilizer package. Phosphorus and potassium are abundant and cheap, but nitrogen, in a form that plants can use, is not. Natural sources include volcanoes and lightning, but by far the majority of natural nitrogen comes from the activities of beneficial bacteria. Organic nitrogen sources consist of the tissues of plants or animals that have been concentrated in some way to render them effective as fertilizer. Cottonseed meal is one example. It contains about 6% nitrogen, and is a good source for the home vegetable gardener. A three pound bag costs $8.72, including tax, at my local garden center. Since six percent of the contents of the bag is nitrogen, the weight of the nitrogen is 0.18 pounds. (.06 X 3) Dividing the cost by the weight of nitrogen yields a value of $48.45 per pound of nitrogen.

We can use this same method to calculate the relative cost of any nitrogen source. Earthworm castings were on offer at another store I frequent. The best price was $43.69, including tax, for a 30-pound bag. The label says it is 1% nitrogen, so the bag contains 0.3 pounds of nitrogen, at a cost of $145.63 per pound!

Bear in mind that in both cases, nitrogen fixed by soil bacteria was taken up by plants that were in turn processed (either by worms or a cotton gin) into a usable material. This material then had to be packaged and transported, all at additional cost. The less concentrated the nitrogen source, the more transportation costs add up. At one percent nitrogen, you have to ship 99 pounds of inert material for every pound of nitrogen. Understanding this, you can begin to understand the costs.

Now let’s calculate the cost for artificially-fixed nitrogen. This is what is added to chemical fertilizer mix. A 40-pound bag of 10% nitrogen fertilizer at Lowe’s is $18 with tax. If you do the math, you will find the cost per pound of nitrogen is $4.50. Unfortunately, the external costs of producing this nitrogen by artificial means are not taken into account. The energy required to produce ammonia or other forms of nitrogen that can be utilized by crops is produced at the cost of large amounts of carbon dioxide and other kinds of pollution, because natural gas is both the feedstock and the energy source for the process.

According to a publication from Iowa State University:

“ Due to the consumption of natural gas as an energy source and as feedstock in ammonia produc­tion, the price of N fertilizer is typically related to supply and price of natural gas. A modern ammonia production plant requires net energy consumption of approximately 29.7 million BTUs per ton of N (Kongshaug and Jenssen). Upgrading ammonia to other N fertilizers requires even more energy: 35.9 million and 31.4 million BTUs per ton for urea and urea/ammonium nitrate manufacture, respectively. “

This is equivalent to burning a gallon of diesel fuel for every 10 pounds of fixed nitrogen thus obtained, in terms of the energy needed. But how much diesel fuel was needed to move the earthworm castings from their source to Knoxville? Ten pounds of nitrogen would be half a ton of bagged worm poo. Calculations far more complex than the ones above would be needed to accurately compare the overall environmental cost of various forms of fertilizer. How much energy was expended, for example, to grow the cotton that ended up in my cottonseed meal? Were pesticides involved? No labeling requirement, to my knowledge, exists for soil amendments.

Conscientious gardeners everywhere might benefit from having this knowledge, but it is not easy to obtain.