Many inexperienced gardeners repeat the same mistakes each year, yet are baffled about why their tomatoes fail to perform like their neighbors. There are several common reasons why tomatoes fail to perform as expected and they all revolve around your choices as a gardener.
1. Choosing stressed tomato seedlings. Many greenhouses and nurseries offer a host of tomato seedlings for sale. Many have grown to a height of a foot or more, but as rule, these plants are already stressed, as they have been overcrowded or lack adequate light. Look for short stocky tomato plants for the best results. The thicker the stem of the seedling, the better it will perform in the outdoor environment. Those that have grown tall and spindly have weak stalks that will break easily. Choose tomato seedlings 8 to 10 inches high with a thick stalk and healthy green foliage.
2. Choosing the wrong tomato cultivar. Not all tomatoes perform well in all environments. Look for a cultivar known to be successful in your area. The number of days to maturity must be less than the number of frost-free days in your area. Because Aunt Betty grows delicious beefsteak tomatoes in her home garden in the south doesn’t mean you can grow them in a northern climate. Choosing the right cultivar for your location improves your chances of success.
3. Buying tomato seedlings too early. Many gardeners are anxious to get started with their garden and buy tomato plants too early. Wait until two weeks before planting to buy tomato seedlings. You may think you can “keep them alive” inside the home until planting time, but the truth is unless you have your own greenhouse, you simply can’t provide ideal conditions for tomato seedlings in the home. Don’t risk stressing the seedlings by keeping them in the home for more than a week or two. Leave them in the greenhouse where they will thrive.
4. Not hardening off tomato seedlings. Some gardeners overlook the value of hardening off their tomato plants before transplanting them to the garden. Hardening off involves acclimating the seedlings to the outside conditions and should take a week or more of gradual exposure to the elements. For more information on hardening off tomato seedlings see Growing Tomatoes: Hardening Off Tomato Plants.
5. Setting out tomato plants too early. In their zeal to get their tomatoes in the ground, home gardeners often “set out” their tomato seedlings before the weather has sufficiently warmed for them to thrive. Don’t be fooled into thinking because the danger of frost has passed that it is automatically time to plant your tomatoes. If temperatures drop below 50-55 degrees Fahrenheit at night, you tomato plants will suffer. Some estimate that the shock of cool nighttime temperature may set your plants back for 30 days. Planting them too early may result in delayed growth
Observing these simple guidelines for buying and planting your tomato seedlings, will improve your chances of producing an abundant crop of vine-ripe tomatoes in your home garden.
University of New Hampshire Extension: Growing Tomatoes
Clemson University Extension: Tomato