Mid-Season Tomato Plant Care
By Anita Galeana

Once you have chosen the recommended Lycopersicon esculentum variety for your climate zone, prepared your garden bed or soil, and carefully transplanted the strongest seedling (6–8 inches) into your sunniest garden location, there are a few tips for proper care of your tomato plants.

Early life and culture of young tomato plants is important to the long-term health of the plant and fruit yield at harvest time. Young seedlings need water, light (6–8 hours of direct sunlight) and air circulation to survive. Newly planted seedlings should be watered carefully around the soil, taking care not to wet the foliage. Drip irrigation or a soaker hose that applies water slowly is best. Outside temperatures, wind and soil structure will determine how often you need to water. Generally, the soil around new tomato transplants should be kept moist for the first few weeks. Once they are established, water when the soil is dry at a depth of 2–3 inches. Less frequent watering will encourage deeper roots.
The warmer the soil, the faster the plants will grow and mulching the plants with a thick layer of straw will keep the soil temperatures more even, and warmer. The tomato plants will require less watering because mulching slows evaporation of moisture. Alfalfa is a good mulch and adds nitrogen to the soil. Straw is also a good option. I’ve grown cherry tomatoes that thrived on only a deep watering every 3 weeks.


Knowing your soil will help determine the application of added nitrogen. For instance, if you added manure to your garden bed or worked in a lot of compost, it may not be necessary to add extra nitrogen at planting time. It’s best practice to wait until the first fruit set and fertilize every 4–6 weeks after. Good organic sources of nitrogen include fish meal, blood meal worm castings and soybean meal. Applying too much nitrogen will result in large green leaves, and also delays flowering and fruit set.

Tomato plants, whether determinate or indeterminate, benefit from support or staking. It allows more plants to be grown in the same bed, keeps the plants off the ground, which reduces fruit rot and it’s easier to harvest the fruit. Metal cages, wooden stakes or tying plants to a fence or other support systems are all acceptable methods of support.
Remember to write down the number of days to maturity, especially if you have multiple varieties and observe your plants frequently for signs of disease or pests.

Sources
http://ucce.ucdavis.edu/files/repositoryfiles/8159-54222.pdf
California Master Gardener Handbook, 2002 University of California ANR Publication 3382
About Anita Galeana
Anita has been a UC Master Gardener with San Mateo San Francisco Counties since 2014.
Her favorite volunteer job is working the UC Cooperative Extension MG help line; helping individuals find solutions to home horticultural problems in the Bay Area. At home she enjoys composting, growing tomatoes, edibles and herbs for her kitchen. She loves experimenting with drought tolerant plants and succulents.
Her garden is a registered wildlife sanctuary which supports a variety of pollinators; including bees, butterflies and hummingbirds.
Anita’s favorite hobby in and out of the garden is nature photography. 🌺
UCCE Master Gardeners
Do you have a gardening question or problem? The UCCE Master Gardeners can help! Contact the HelpLine — our UC-certified Master Gardener volunteers are standing by to provide you with research-based home horticulture advice. Email us your question and details anytime, along with close-up photos. Alternately, you can leave us a voicemail, stop by in person, or ask your question via social media @SFBayGardeners. Don’t forget to provide your contact information so we can get back in touch with you.




HelpLine: mgsmsf@ucanr.edu
Mon & Thu, 9am-4pm (closed holidays)
(650) 276–7430 (voicemail only)
@SFBayGardeners
1500 Purisima Creek Road
Half Moon Bay, CA, 94019
