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Friday, July 29, 2011

Tomatoes: All Vines And No Fruit

Sunburn on tomato fruit due to lack of leaf cover
Q. The 1st year that I had tomatoes, they were fantastic. I had so many tomatoes that I had a hard time giving them away, but the sun baked the plants ant the remaining tomatoes turned white from the blazing sun. As a result I made some shade for them (it was too late). The next year I put the shade over them and added Miracle Grow to them. They grew like crazy right through the roof ZERO FRUIT (someone told me that it was the Miracle Grow). This year I used a low nitrogen food something like 5-8-9, and one day the plants were wilting (I thought from the sun, So I shaded them. Oops.). They are still really blooming. Is there a time when the shade sould be applied? Talk about rocket science, man...I think I need a how to grow tomatoes instruction book that includes all the don't you do thises. Is such an animal available?

Tomatoes growing under 30% shade
A. When growing tomatoes you have to be careful about how much nitrogen that you apply or you will get all vines and no fruit for about 3 to 4 weeks until the nitrogen begins to run out and then they will start to flower and set fruit. I normally fertilize with high phosphorus and a moderate nitrogen fertilizer at the time of planting and do not fertilize again until I see flowers and fruit beginning to set. Once that happens, I then begin to fertilize lightly again and do so monthly. It is not the Miracle Gro. It is the amount of Miracle Gro that you applied. The fertilizer ratio that you selected might also have something to do with it. High nitrogen encourages leaf and stem growth. High phosphorus encourages flower, fruit, root development, seed and oil production.

Heirloom tomato grown in the desert
There are some people in town who are telling people that Miracle Gro is like crack for plants. This is entirely untrue. I have been using Miracle Grow, Rapid Gro, Peters and other similar mineral fertilizers for over 30 years and have found this to be the furthest from the truth. However, it does not substitute for good soil preparation and the use of compost, plenty of it, for soil bed preparation. Products like Miracle Gro should be used as supplements to enhance plant growth, not as a substitute for good soil preparation. My orchard manager did exactly the same thing as you did last fall with our tomatoes. He did not carefully apply fertilizers at about ¼ the amount on the fertilizer label. This was after the soil had been prepared in the spring. He applied the full amount for fall production of tomatoes. He got great tomato Vines and no fruit. This was after careful instructions by me not to do that but he thought if a little is good and more is better. All totally wrong! He learned a valuable lesson and we lost our fruit.

Next is your shade. If you are growing crops that flower and set fruit then do not exceed 30% shade. This includes tomatoes, peppers, eggplant, squash, melons, etc. If you are growing vegetables that you harvest for their leaves then you can increase the % of shade up to about 50%. Too much shade will cause plants that flower to reduce the number of flowers they produce, have leaves that are larger and more tender, and stems that are longer between the leaves they produce. In other words they tend to grow larger and “stretch” in their growth. Okra should not be grown in the shade. It loves full sun and lots of it. It will not perform well under any kind of shade cloth. I hope this helps.

There is not a good primer for growing vegetables in our climate. I am currently putting together some classes with a local nursery on vegetable, fruit growing and principles of landscape design for the desert. I will keep you in notified as they develop.


  1. I had problems with my tomatoes last year, but this year, I built a wood frame over my garden using 2x4s and 4x4s, then covered the top and sides (west and south facing) with green shade fabric. using a raised bed garden, I improved the soil before planting, then used a shredded pine mat on top of the soil.
    While wanting to conserve water, I found it works best to water the plants every couple of days, say for 10 minutes or so, and sometimes in late afternoon. So far my 4 plants have produced about 5 5-gallon bucketfulls of tomatoes. The mulch I used has kept the dodder under control, and verticulum is minor compared to other years, inspite of sprinkler type watering.

    Let me explain the mulch that I use-
    I went to Little Baja one day, out by the silverton hotel, and in their garbage can was shredded pine or wood packing material (sort of like the type used to pad a swamp cooler). free for the taking. I covered my vegetable gardens with that stuff, and covered the mulch with compost. I have a LOT LESS weeds, and the plants are doing well. Maybe you ought to try it

  2. Thanks for the comment, Col. Klink. We will have to give it a try. Any way we can recycle this stuff.