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- Drawing: Texas A & M Univ. by T. Kohlleppel and D. Lineberger
Like their cousins, potatoes, tomatoes are a member of the nightshade family native to South America and were once thought to be poisonous. Their genus name means, literally, “wolf peach” … peach for their shape and size and wolf for their (presumed) poisonous characteristic.
This post starts off a 6-part cultivation fact sheet. Over time, as revisions are suggested, it will grow into a one-size fits all resource that you can refer others to with confidence.
Genus: Lycopersicum esculentum
Variety: all
Broad types:
Generally speaking, tomatoes are classified as either determinate or indeterminate. Determinate tomatoes bear flowers at the top of the main stem, indeterminate tomatoes will use that stem for further growing (I have known 3 lb. ripe fruit at the 11′ mark on ‘Mortgage Lifter’ tomatoes grown on a 10′ tall trellis.) and, instead, set their flowers and fruit on the stalks growing off to the side for that purpose. To halt the upward growth of indeterminate tomatoes, pinch out the growing tip. The terms “high acid” and “low acid” are misnomers. They should be ‘”low sugar” and “high sugar”, respectively. The acid content remains relatively stable across all varieties of tomatoes, but can be masked by variations in the level of sugars. The terms “potato leafed” and “non-potato leafed” are principally useful in identifying heirloom varieties and there only as a general rule. The “potato leafed” varieties are more likely to be heirloom than the “non-potato leafed” … but there can be no certainty in the matter based on leaf shape alone.
Annual / Perennial:
Technically, tomatoes are a perennial, but in Michigan they are not expected to survive our winters. If protected from last and first frosts, experience shows that the season may be extended by a month or more at each end of the growing season for a total of as much as 10 months. This is due to the fact that first and last frosts are often isolated events with good growing weather before the first frost and after the first one. Planting before the soil has warmed will not result in an earlier yield but may result in a sturdier, better rooted, plant. In a backyard garden, it is nearly impossible to quantify the benefits of such pre-season growth but experience has shown that planting tomatoes deep and early leads to reliably good yields. The key is to accelerate the warming of the soil before planting. Raised beds, clear plastic sheeting, high unfinished organic content, wind-sheltered location and east-west orientation of the beds all speed the warming. Clear plastic or glass cloches applied after planting further accelerate this process. If un-vented, be careful to remove the cloches on sunny days to prevent over-heating. The overheating is an invitation to fast-growing weak plants and fungal diseases. If using plastic bottles such as gallon milk jugs or 2-liter (or bigger) soda bottles, either remove the entire bottle during the day or at least remove the cap.
Propagation:
While young tomato plants are available in local nurseries, there are over 200 varieties to choose from in the seed catalogs. Most nurseries will have only the same 5-6 hybrids plus maybe one or two heirloom varieties. Because of this, and because it is simple to do, many gardeners will choose to start their own plants indoors. Plant indoors, 6-8 weeks (March 15 – April 1) before average last frost date (May 15 in USDA zone 5, adjust these dates to your local conditions) in peat pots, cell packs, paper / Styrofoam cups (poke hole in bottom for drainage) or homemade newsprint cells. Choose a good planting media without fertilizer and add up to 50% perlite. When the plants sprout, begin misting with a light application of fish-based fertilizer.
