How to Take the Confusion out of Buying Tomato Seeds
Tomatoes are the number one vegetable grown in America and starting your own seed is a good way to guarantee the plants are free from nursery-borne diseases. When looking at tomato seed descriptions on a seed package or in a catalogue, some of the terms can be confusing. Here’s some information to help you understand what it all means:
To start, here are a few of my favorite sources for tomato seeds:
When looking at seed descriptions you will first notice the words indeterminate and determinate.
Indeterminate means that the plant grows as a vine and should continue to produce all season-if the growing conditions are suitable. That means the vine will produce as long as there is enough fertilizer and moisture available and the temperatures stay between 50 degrees F at night and 90 degrees F during the day. Indeterminate plants need support because the fruit cannot set on the ground or it will rot. Examples of indeterminate tomatoes are most heirloom varieties such as Brandywine, and hybrid varieties Champion, Early Girl, Jubilee, and Lemon boy as well as cherry types such as sweet 100.
Determinate varieties produce over a short time frame-usually six-eight weeks-and grow a short vine or a bush. They are best for areas with hot summers where daytime temperatures are consistently over 90 degrees F. That is because the plants can produce in late spring and early summer then decline as heat and summer pests, or freezing weather in the fall, kills them. Plant new determinate plants in July for a fall crop of tomatoes in Central Texas. Examples of determinate varieties are: Celebrity, Rutgers, and Roma.
When you look at the description of hybrid tomatoes, you will notice one of these letters or a combination of letters: V, F, FF, N, T, A, or S. These symbols designate a particular disease resistance bred into the plant. You will not see these symbols on a package of heirloom tomato seed, which do not have any disease resistance bred into them like the hybrids. Here is what disease each of the letters stand for:
V: Verticillium Wilt-causes yellowing of lower leaves and weakens plants.
F: Fusarium Wilt-Lives in the soil, bacteria clogs stems eventually killing plants.
FF: Fusarium Wilt races 1 and 2-Same as F
N: Root Knot Nematodes-Prevalent in Sandy Soil. Infects roots cutting off moisture and nutrient supply.
T: Tobacco Mosaic Virus-Results in leaf distortion and mottling of leaves and fruit.
A: Alternaria Leaf Blight-Also known as early blight or leaf spot. Produces black spot on leaves.
S: Stemphylium-A type of fungus appearing as grey leaf spots and fruit rot.
Of course you want to buy a variety that's resistant to as many diseases as possible, but few varieties are resistant to all of them. In our area, the most important are V,F, FF and T. Add N if you are planting in sandy soil. Good sanitation practices are the best means of disease control. Also, never use tobacco around tomato plants because you can spread the tobacco mosaic virus to them from your contaminated hands or clothing.
Small and medium fruited varieties grow best in warmer climates as the weather heats up in the summer. Some varieties like Solar Flare and Sun Leaper may produce in warmer weather. My experience with them in Texas has not been very good, but you should never be afraid to try anything new.
After buying your tomato seed, start seedlings by placing seeds 1/2 inch deep in new potting soil or sterile potting mix in a well drained container. Keep the containers moist and at 80 degrees F in a bright spot, so new plants appearing in a week don't get leggy. Set the plants outside in the sunshine, while the weather is not freezing, to harden off and plant outside when all danger of frost is passed.
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Tomatoes are the number one vegetable grown in America and starting your own seed is a good way to guarantee the plants are free from nursery-borne diseases. When looking at tomato seed descriptions on a seed package or in a catalogue, some of the terms can be confusing. Here’s some information to help you understand what it all means:
