Thank goodness, tomato planting time is here!
Finally Memorial Day is here; the traditional tomato planting time for our region. Lately the weather has been warm both day and night, close to the ideal growing conditions for tomatoes with the daytime air temperature in the 70s, and the night temperature above 50. Night temperatures below 50 degrees will slow tomato growth, so don’t be in too much of a hurry to get your plants into the ground if cold nights are forecast. Plants stressed early in life can fail to recover fully.
If you garden in a cold pocket there are a few tricks you can employ to keep the plants warm at night. Try covering them with reemay to hold the heat at night and use mulch to warm the soil. Black plastic will help heat things up, or you can try red plastic mulch, which is reputed to warm the soil and conserve moisture much like black plastic but has the added feature of improving tomato yields 10 to 20 percent. Whether you use plastic, straw, shredded leaves, grass clippings, or a thick layer of newspapers to conserve moisture, some form of mulch is recommended.
Any gardening success story begins with the soil. Have yours tested and bring the nutrient levels up to snuff before you begin planting. The pH level should be around 6.5 for optimum tomato growth. Tomatoes are heavy feeders, but too much high nitrogen fertilizer will cause the plants to produce lots of foliage at the expense of flowers and fruit. Use a low nitrogen, slow release soil enhancer, like compost or well-aged manure. Kelp is full of minerals essential to healthy tomato growth. Yellow leaves are a sign that more nitrogen is needed. Leaves will be purple if the plants are lacking phosphorus. Fish emulsion or other water-soluble fertilizer should remedy the problem.
Unless you are growing grafted plants (more about them later), it is safe to plant tomato seedlings much deeper than they grew in the pot. This encourages them to grow more roots along the buried stem, with which they will draw nutrients and water from the soil. If your seedlings got too tall and leggy, after removing all but the top four to six leaves, plant them on their sides in a trench, burying most of the stem. New roots will form along the stem, making the plants stronger. Stake your plants when transplanting to avoid severing the stems or damaging the roots later. Tomatoes are tall, vining plants and need some kind of support. Whether you trellis, stake or cage, do something to get your plants up off the ground and you’ll get a higher yield of better quality fruit.
It makes sense to grow varieties that are best suited for our region and growing conditions. I have had great luck with both heirlooms and hybrids, especially those that originated in cold Eastern European countries. Some short season varieties (65 to 70 days) with good flavor are: “Anna Russian,” “Black Krim,” and “Early Goliath.” Some of our favorite mid to late season varieties are: “Soldacki,” “Delicious,” “Goliath,” “Amish Paste,” “Better Boy,” “Omar’s Lebanese,” “Kellogg’s Breakfast” and “Sun Gold.” Just call me crazy (you won’t be the first to do so) but this year I have 36 different varieties to plant.
I had the pleasure of attending a talk by one of my horticultural heroes, Barbara Damrosch, at the Boston Flower Show in March. She and her husband, Eliot Coleman, have a market garden in Maine and each has written several books on gardening. She also recommends growing a mix of heirlooms and hybrids. Her favorite varieties are “Big Beef,” “Brandy Boy,” “Stupice” and “Rose.” She admits, though, that in the long run, it doesn’t really matter what varieties you have chosen, since even the worst home-grown tomato tastes better than a store-bought one!
Whether or not to pinch back your tomatoes is mainly a matter of personal choice, but there are a few caveats. You definitely don’t want to prune determinate varieties or you won’t get much fruit. Since determinates bear fruit only on the ends of their branches, never clip them off or you won’t get any fruit at all. Once flowers form at the vine tips, the plants will stop growing and put all their energy into fruit formation. Bush varieties are all determinates.
Indeterminates keep growing and producing fruit until they are killed by frost. They can be topped above the highest bloom in late summer to keep them in bounds and encourage green fruit to ripen.
Damrosch removes the suckers that form near the base of the plant and controls the growth of exuberant plants by continuing to pinch out the suckers that form in the leaf axils over the summer.
Don’t feel like you have failed as a gardener if you don’t do it. The flavor of your tomatoes will not be adversely affected and unpruned plants yield more fruit than pruned ones do – it just takes longer to ripen. Later in the summer if you feel the need to thin the plants out a bit to get more sunlight in to hasten ripening, do so.
An even supply of water is critical for juicy, succulent tomatoes and Mother Nature may not cooperate by providing the necessary 1 to- 11∕2 inches of rainfall per week. If you have to water, do it deeply. Frequent light watering will encourage weak, shallow root growth. Stop watering when the fruits are full size or the flavor will be diluted and bland. Collect and use rainwater instead of city water that may have harmful chemicals in it. Rather than using an overhead sprinkler, water at the base of the plant to avoid wetting the foliage or splashing soil on the plants, which can introduce disease.
There is a trend toward growing grafted tomato plants. I’m not sure if this is the best idea since sliced bread or just a way to get us to spend $10 for a 75-cent plant.
Used in Europe and Asia for years, a grafted plant is formed by fusing the young s hoot of a tasty variety onto a vigorous, disease-resistant, rootstock plant. Greenhouse growers who use the same planting area year after year swear by these rugged plants, claiming they bear three or four times more fruit than ungrafted plants. Damrosch has grown them for several years and says that fruit production is greatly increased.
Commonly the top plant is an heirloom with great flavor that normally has low yields and little or no disease resistance, while the bottom plant has roots that will flourish in less than perfect conditions.
Making these grafts is an exacting science, not something the average home gardener can do, hence the steep price.
They are very popular with organic heirloom growers who use high tunnels – hey that’s me! Maybe I should quit being such a curmudgeon and give them a try.
Times have changed, and now a fruit that was once thought to be poisonous and inedible is the most popular vegetable grown by home gardeners. Just one bite of a vine-ripened, home-grown tomato will have you convinced that nothing could be more delicious.
If you would like to read more of Barbara Damrosch’s gardening wisdom, look for her books The Four Season Farm Gardener’s Cookbook and The Garden Primer or follow her weekly column “A Cook’s Garden” in the Washington Post.