Tomatoes are one of the joys of summer. Many people anticipate the first field-grown tomatoes with the same enthusiasm as the first strawberry or peach. Growing one’s own strawberries or peaches is a pretty tough undertaking for the average home gardener (although dedicated gardeners can do it!); homegrown tomatoes are a more accessible challenge for the weekend gardener. However, growing a really good tomato is not child’s play — it takes knowledge, planning and solid execution to culminate in a tomato sandwich for the ages. Here are a few tips to help you get that delicious red fruit to the kitchen table.
No. 1: Start fresh. Have you been growing tomatoes for a few years? Having sufficient garden space is often a challenge, however, when you plant tomatoes in the same spot as you did last year, or even the same spot used within the past two years, you’re asking for problems. There are numerous diseases (root knot nematodes, Fusarium wilt, Verticillium wilt, and late blight) which reside in the soil and are just waiting to attack a new crop of tomato plants. Refrain from planting tomatoes in the same spot more than once every four years (and not just tomatoes: it includes every plant in the solanaceae family, which includes tomatoes, peppers, eggplants, and potatoes). By rotating crops, it reduces the chance of a disease buildup in the soil which will take your plants down.
No. 2: Soil prep. Garden soil must have a pH between 6.2 and 6.8 to grow a successful bounty of fruits and vegetables (there are a couple of exceptions on the upper and lower end of the scale, but this is true for most produce). Our native soil, unimproved, can have a pH as low as 4.5, so unless lime has been added within the past three years, it is likely your soil pH is too low to grow good vegetables. A soil test will tell you how much lime to add to your soil. Having a soil test and knowing, not guessing, how much lime to put out is always optimal. You will spend a lot of money, as well as blood, sweat, and tears, on your garden, so don’t skimp on this part. Lime is relatively inexpensive, so putting out the correct amount is one of the best and cheapest things you can do to help insure a productive garden.
One thing money can’t buy? Time. It takes four-six months for lime to modify the soil pH. So, if it’s April and your soil report says your pH is 5.5, no amount of lime can be applied to raise the pH for a crop planted in May. However, there is an option. Some composts are high in pH, and by amending your garden soil with compost, it may raise the pH sufficiently. In addition, compost adds organic matter, which is critically important in our sandy soils. Organic matter provides water and nutrient holding capacity, both of which are lacking in our soils. Proper soil pH and amending the soil are two critical steps in growing good tomatoes.
No. 3: Water consistently, not too much and not too little. Once tomato plants start to put on fruit, consistent watering is critically important. As anyone who has eaten a ripe tomato knows, they are full of water. If plants receive insufficient water, then get a lot of water at one time, a rapid expansion of the fruit can lead to splits and cracks.
Another water related problem is blossom end rot, a common disease in tomatoes. BER is considered an “abiotic” disease, as it’s caused not by a pathogen but rather by environmental or nutritional conditions. Tomatoes with BER have blackened, flat bottoms on the fruit. It is caused by lack of calcium in the developing tissues. While the technical cause of BER is lack of calcium, there are other factors frequently involved. If the soil pH is correct (see No. 2 above), sufficient calcium should be available. However, calcium is considered an “immobile nutrient” — in other words, it is hard to move it through the plant. Consistent watering, without allowing the plant to dry out, helps keep the calcium moving so that it is present in the developing fruit. There are times when summer temperatures get into the 90s for several days that no amount of watering will prevent BER. Often you will see blossoms aborting, dropping off the plant without being fertilized due to high temperatures, as well. However, once those extreme temperatures abate, you’ll see fruit without BER if all other conditions are sufficient.
These are just a few tips to help get your tomato growing off to a good start. Fertilizing, variety selection and many other factors (including luck!) all come into play. Here’s to the best tomato season yet!
Paige Burns is assistant horticulture agent at the N.C. Cooperative Extension’s Richmond County office.