Marin Master Gardeners
University of California
Marin Master Gardeners

Tomato Q & A

Tomatoes Graphic

1.  What is the best tomato for my area?
      In areas with less sun, choose smaller size tomatoes with shorter maturing times. Well amended soil will give you the best tasting tomatoes. They also need at least 6 hours of sun a day, and night and soil temperatures of 55 degrees. 

2.  What is the difference between “heirloom” and “hybrid” tomatoes?
     Hybrid tomatoes are cross bred from two or more different plants and they are created for a particular purpose (disease resistance, color, shape, etc.). Their seeds will revert back to one of the parents, so they are not reliable to grow from saved seed. Heirlooms are open-pollinated and the seeds have been handed down through generation of growers, and they are at least 50 years old. They are valued for their taste, unusual markings color and shape. They can be grown from saved seed and replicate the original plant. 
 
3.  What is the difference between “indeterminate” and “determinate” tomatoes?
     Determinate, or “bush” tomatoes grow to 3-4 feet. They stop growing when fruit sets on the top bud. Fruit ripens at about the same time over a 4-6 week period. They need little support and are well suited for container gardening. Indeterminate tomatoes will grow and produce fruit until they freeze. They can grow from 6-12 feet tall and they need strong support.
 
4.  What does “days to maturity” mean?
     It means the number of days from transplanting the seedlings into the garden until the first appearance of mature fruit.
 
5.  What does “disease resistance” mean?
     The ability of a plant to withstand attack from such things as fungi,viruses, and bacterias is it’s level of disease resistance. The common disease resistance in our area (Marin County) is from verticillium wilt (V), fusarium wilt (F), and nematode (N).
 
6. Where and when to plant?
    Plant 3 to 4 weeks after the frost free date in your area when the night time temperature and soil are about 55 degrees (around May 1). Choose the sunniest spot–tomatoes need a minimum of 6 hours of sun each day. Provide well draining soil because good tasting fruit comes from rich, healthy, well amended soil. Place plants about 3 feet apart.
     
7.  How to plant?
     Dig a hole to accommodate the plant up to the top 2-3 inches of foliage (new growth will form on buried stems). Remove any flowers or buds. Add compost and fertilizer (pellet form of a balanced fertilizer) to the hole. Place plant in the hole, replace the soil and water well at the base of the plant. Stake your tomato at the time of planting. Then mulch, mulch, much!
 
8.  Continuing care?
     You may choose to feed again at the time of fruit set . Use a fertilizer higher in phosphorus rather than nitrogen. Too much nitrogen will give you lovely foliage, but less fruit. Cut watering back to once a week (about 1 inch of water) as plants mature. Potted plants will need more frequent watering. Do not over-water or over- fertilize, and keep the foliage dry to prevent disease.
 
9. When to harvest?
    Harvest when the fruit is well colored and soft, but not mushy. As tomatoes begin; to color, they can be picked to finish ripening indoors. Tomatoes will be ready to harvest about 6 weeks after they start to blossom.
 
10. Websites?
      There are many websites about tomatoes. These are a few that have helpful information.  
Prepared by Jean Sugiyama
Marin Master Gardener
Webmaster Email: banielsen@ucanr.edu