Summer Tomatoes: What to Do Now for a Successful Season

Apr 1, 2023

If you want to enjoy your own fresh, homegrown tomatoes this summer, April is the time to get started. Unless you are a hardcore gardener and start your own from seeds, most likely you will be buying young tomato plants (“seedlings”) from a nursery or plant sale. More about that later! Once you have your plants home, knowing what comes next is important to ensure that they remain healthy and productive later on. Here's how:

Be patient
You'll probably start seeing tomato plants for sale in nurseries and big box stores in February but unless you have a place to keep them happy until the weather warms up, be strong and resist the temptation to buy. Tomatoes that are planted too early are much more susceptible to a variety of diseases. Wait until nighttime temperatures are reliably above 50°F and daytime temperatures are well above 55°F. In cool coastal locations, it might be late April or early May before it warms up into the 60's and 70's so selecting tomato varieties with the right number of days to maturity (“DTM”) for your location is key.
Be prepared
Choose a spot in your garden, deck, or balcony that receives at least 6 hours of direct sun every day. Whether you plant in the ground or in a container, amend the soil with plenty of organic matter (compost, worm castings, etc.) and check to make sure that there is good drainage.

Plant properly
Dig a hole about 8 inches deeper and wider than your tomato plant. Make sure to space your planting holes far enough apart to leave enough room for mature plants. The soil should be loose and easy to work with your hands. Add organic bone meal, a source of trace minerals (such as Azumite) and a handful of alfalfa pellets to the hole and mix into the soil. Add back a portion of the soil so that the hole will accommodate the plant up to the lowest branches. This will help stabilize the plant and give the roots a head start. Gently remove the seedling from the container by squeezing gently on all sides and set it in the prepared hole. Fill the hole with remaining soil and press down lightly. Water carefully to settle the soil around the roots and remove air pockets. Do not allow water to splash on the ground and back onto the plant, which will spread soil borne diseases to the plant. Once your plants have developed more leaves, remove the lowest branches if splashing is a concern.

Provide support
Most tomatoes need some type of stake, cage or trellis to prevent fruit from touching the ground and to keep branches from bending and breaking. This is particularly true of indeterminate varieties, which continue growing throughout the season. There are many types to choose from and you may even be inspired to invent your own! Once you choose the option that works best for your situation, install it soon after your planting is complete.

Water wisely
Water your plants regularly to keep the soil evenly moist but not soggy. In general, tomatoes need approximately 1-2 inches of water per week. Check the soil by inserting a skewer or stick a few inches into the ground near the edge of planting hole. It should feel moist but not too wet. Signs that your tomatoes are not getting enough water include drooping stems and wilting leaves. Later, tomatoes that don't get enough water may split or fall off. A condition known as “blossom end rot” (BER), where tomatoes turn brown opposite the stem, is caused by a complex interaction of available water and the plant's ability to take up calcium.
Feed them well
Tomatoes are heavy feeders and will need to be fertilized regularly. After plants are established and beginning to set fruit, apply a liquid organic fertilizer all around the base of the plant about 6 inches from the main stem. This should be done about every two weeks until the end of the season. If you opt for a dry organic tomato fertilizer, work it lightly into the top layer of soil and then water the plants.
Be alert to pests
Observe your tomato plants for signs of pest infestation or disease. Anything suspicious should be identified quickly to prevent spreading. Watch for pests like whiteflies, leafminers, tomato hornworms, aphids, and blight. More information can be found here:
Days to maturity
Depending on the variety, it may take anywhere from 60 to 90 days for tomatoes to produce fruit. This is known as “Days to Maturity.” Since cooler climates have fewer days with the warm temperatures tomatoes need, the growing season in these areas is shorter. This means that tomato plants requiring fewer days to reach maturity will be more successful in these areas.
The fruits of your labors
When tomatoes are fully- colored and firm but yield slightly to the touch, they are ready to harvest. Using clean pruning shears, look for a small, thickened area on the stem near the tomato and snip just above that spot. Leaving that bit of stem will help preserve the flavor until you are ready to enjoy the fruits of your labors. Be sure to store your tomatoes at room temperature with the stem side down to maintain freshness. More information can be found here:

Cynthia Nations is a UC Master Gardener coastside resident who grows many different varieties of tomatoes each summer. This article was edited by UC Master Gardener, Maggie Mah.


By Cynthia Nations
By Maggie Mah

Attached Images: