Growing Better Tomatoes - May 26, 2004
Jeff Schalau, County Director, Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County


Every vegetable gardener anticipates harvesting that first, vine-ripened tomato from the garden. However, growing your own tomatoes can be as challenging as it is rewarding. By anticipating a few of the hurdles and monitoring your progress, you will increase your yield and have higher quality tomatoes.

Soil preparation and providing the proper growing space will get your tomatoes off to a good start. Tomatoes grow best in deep, loamy soils in an area that receives at least six hours of full sun. Add lots of well composted organic matter, fertilizer, and a small handful of soil sulfur to each planting hole. Too much nitrogen fertilizer can lead to excess vegetative growth and less fruit production, so the fertilizer should be twice as high in phosphorus as it is in nitrogen (for example 5-10-10 or 8-16-16). If plants appear to need a growing boost, then give them a second fertilizer application after the first fruit has set. Tomatoes should be spaced no closer than 24 inches between plants and I feel 36 inches is better.

Tomatoes are easily grown from seed, but it is too late to start plants from seed this year. Nurseries carry plants of the most common varieties and a few heirloom varieties. Many newer nursery grown varieties also have capital letters on the label. These may look something like "VFFNTA". The letters refer to their resistance to common tomato diseases. V stands for verticillium wilt, F for fusarium (multiple F's stand for variety a and b). N for nematodes, T for tobacco mosaic virus, and A for alternaria stem rot canker.

Tomatoes are usually categorized as early, mid-season or late. Another consideration is whether the tomato cultivar you choose is determinate or indeterminate in growth habit. Determinate (D) tomato plants grow to a certain height and then stop. They also flower and set all their fruit within a relatively short period of time. This is an advantage if the tomatoes are being grown primarily for canning purposes. Indeterminate tomato plants grow, flower, and set fruit over the entire growing season.

When purchasing tomato transplants, choose those with straight, sturdy stems about the thickness of a pencil. They should have 4 to 6 young true leaves, no blossoms or fruit, and be free of insect pests and diseases. Plants in individual containers or cell packs experience little or no transplant shock and become established quickly. Tomato plants will develop roots along the stem and may be set deeply at transplanting with the first set of leaves near the soil surface.

Some folks (like me) prefer to tinker with their garden and manipulate tomato plants by staking them or using cages. Others allow the plants to sprawl every which way across the soil surface. It really doesn't matter which you do, fruit production will be roughly the same either way. On the ground, you may lose some fruit to rot and insect damage. Staking seemingly saves space but will also expose the plant to wind and sap some energy to support the vines.

The major insect pest is the tomato horn worm. Monitor your plants by watching for chewing damage and dark frass pellets on leaves. Simply hand pick and destroy them. Diseases in our area include curly-top virus, root knot nematode, and blossom end rot. Search the Backyard Gardener web site (address provided below) for more information about curly top and root knot nematode. Cracking/splitting of ripening fruit can also be a problem. Some experts think this is related to inconsistent irrigation. However, some tomato varieties are also more prone to splitting. I hope you all enjoy your first homegrown tomatoes as much as I will!

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/.

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: May 20, 2004
Content Questions/Comments: jschalau@ag.arizona.edu
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