Knowledgebase

Tomato productivity #818663

Asked January 16, 2023, 12:44 PM EST

I have two sources of frustration with tomatoes in my home garden: Late harvest, and profuse vegetation with seemingly low fruit production. I started this garden plot in 2012. It is located in a very old farmstead and was converted from lawn. I think it’s possible this plot was never plowed for farming or disturbed by construction, as part of the farmstead since the 1880’s. It may have been gardened before, but not for at least 20 or 30 years. It is open to the south, gets full sun with shade starting after about 3 pm in summer. I’m a certified organic farmer, so I don’t use any pesticides or synthetic fertilizers on the garden. In fact, the garden has not had any fertilizer except mulch. I’ve never done a soil test. In the first years of this garden, I had good results. Tomatoes seemed to do well and start to produce sometime in July. They always grew profusely, with lots of lush tops, but also with lots of fruits. I have never experienced problems with late blight, and the plants would often produce fruits until frost. I had to devise staking systems to hold up the lush greenery. I rotate the area used for tomatoes and generally don’t repeat tomatoes in a specific area oftener than 4 years. In the early years I bought potted tomato plants for transplant, but soon started plants from saved seed, using mostly heirloom varieties sourced from Seed Savers Exchange. I would have good-sized plants to transplant in late May or early June. I soon learned to use mulch to control weeds, as I don’t like regular hoeing to keep them down, After experimenting with different mulches, for several years I used grass clippings (no fertilizer or pesticides used on the lawn). I would get some mulch down early and keep adding layers through the year to keep weeds down. This created really nice tilth, and I did not need to till or dig the garden in the spring to loosen the soil. I now use a system of frames to hold up garden netting horizontally, and the tomato plants grow up through the netting for support. I have to use two levels of netting, and the plants would probably reach through a third layer (see photo). I put out 3 plants across the 12’ wide garden, with 3 rows about 40” apart. Gradually the fruit seemed to take longer to set on and ripen, and the tops got lusher and taller. The total yield seemed to reduce as well. The plants would bloom and look fantastic, but fruit was slow to develop and sometimes individual fruits would not develop properly. I would end up with fewer numbers of large fruits, rather than a balance of sizes and lots of total fruit. I began to suspect that the grass clippings had overbalanced the nitrogen in the soil, especially since it was almost always covered with mulch. So I switched first to using grass hay as mulch for a couple of years, and in the last two years to oat straw. In the fall of 2021 I sowed a cover crop of winter rye where the tomatoes would be in summer 2022. I pulled that and put tomatoes in, in June. Last summer’s crop was much the same — lush top growth, slow to fruit (not till the end of August), no late blight, with some fruit till frost, but overall not very good yields. Over the years, I have both used home-grown seedlings and purchased plants. I got hail one year and had to replace all the plants with purchased ones in early June, with the same results. I also have difficulty growing peppers, of various varieties — slow to grow and few fruits. But I have good luck with eggplant. Cucumbers do very well, and salad greens. Brussels sprouts seldom develop good sprouts. Any help would be appreciated! Thanks, Tom Hunter

Wabasha County Minnesota

Expert Response

Usually lush greenery and low fruit indicates too much fertilizer.  However, as you state you do not fertilize, that is not the problem.  My first suggestion is you do a soil test as soon as the soil is workable.  I will give you a link.  I believe the cost is $17.  Secondly, it is possible the netting is acting like a shade cloth and interferring with the sunlight reaching the plants.  I like your supports but consider putting a stake in the center near the stem of your plant and you can tie your plant to the stake and the outer boards will support the branches.  Third, I would like you to take a look at the varieties of plants you are planting.  Late harvest may indicate tomatoes that require a longer growing season.  Many of the heirlooms are 80+ days to maturity.  Consider putting in plants with shorter growing seasons, perhaps 65-70 days.  Peppers need the sunniest, hottest place in your garden.  Maybe even consider putting them in a container.  They do not do well if crowded.  Brussel sprouts mature late and taste better after a light frost.

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Barbara, Anoka County MG, TCA Replied January 16, 2023, 8:22 PM EST

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