Shadegardener said:Thanks for posting those tips, Jim. Ammonium nitrate, huh? I'll have to check into that. I had always heard that if you give tomatoes too much nitrogen that you'll end up with a big healthy plant but few tomatoes. I do plant them with an organic granular fertilizer for vegetables along with crushed egg shells in the planting hole. Usually the first tomato of the season has blossom end rot but not the rest of the crop. I do mulch them with shredded leaves to help with the moisture thing and have a drip hose for when things really get dry. Here, so much of the state of the crop depends on weather - if it's too cool or wet or whatever.
Nitrogen gets an undeserved bad rap, for the most part. It's odd that so many gardening myths exist for the sole purpose of discouraging the use of fertilizers. If you look in most gardening sheds, you're almost guaranteed to find a good number of very old, partially used or unused containers of various plant foods. People are afraid of "burning" their plants, or discouraging fruit production.
At least 20 years ago, when Sunset Magazine had more of a focus on horticulture, they undertook a joint study with the University of California at Davis regarding fertilizer blends and their effectiveness. They ran performance tests on containerized flowering plants, foliage plants and vegetables, using several different formulations of fertilizers, including the high-phosphate "Bloom" fertilizers. It turned out that the best overall performance was achieved with a fertilizer having a high percentage of nitrogen, a somewhat lower percentage of phosphorus, and a lesser amount of potash. Performance was measured by bloom and fruit production. At the time, this macro-element profile corresponded very closely with the formulation of Rapid-Gro, which, at 23-19-17 (with minors), was a little high in P and K for my taste, but I have to say it was amazing stuff. It was sold as crystals intended to be mixed with water, and applied as a soil drench or to foliage. Sunset's conclusion was (paraphrasing) that nitrogen enhanced all aspects of plant growth, resulting in larger plants with bigger root systems and more leaves, which allowed the plants to gather more energy from the sun and, in turn, produce more and bigger fruit or flowers.
Not only were the "bloom" fertilizers the poorest performing of the bunch, but being high in phosphorus, they were the most likely to build up to toxic levels in the soil. Phosphorus is no joke, and should be used carefully, whereas nitrogen and potash tend to be more water-soluble, or transient, in soils. Elsewhere, I read that woody plants generally tend to do just fine with the phosphorus and potash that is present in most good soils. I asked two acquaintances what they used to fertilize their walnut and pear orchards, and they both said "urea".
Rapid-Gro grew everything well, and I was able to sustain under-potted daylilies for years with the stuff. I also used it on my vegetable garden, and everything grew strong and healthy. It was supposed to be mixed at 1 tablespoon per gallon, but I had a friend who (weekly) put over 5 tablespoons in a quart mason jar and poured that around the watering basin of the tomato plants, and then filled the basins with water. Those plants had unbelievably dark green leaves, but never grew rank, and the tomatoes were big and plentiful.
Rapid-Gro was a huge commercial success, but sometime in the 80's the company was "absorbed" by Chevron Chemical, and the product was discontinued. For a while I was buying Miracle-Gro Tomato formula, which was also a high-N, medium-P, low-K formulation, but I see now that their new Tomato food, like most of their fertilizers, is phosphorus-heavy. I just looked at their website, and found that their "new" Liqui-Feed is 12-4-8, which is ideal. Unfortunately, since it's already in liquid form, it's likely to be very expensive. With the advent of "Indoor Gardening", there are a lot of specialty fertilizers available now with good nutrient profiles, and you can even formulate your own.
None of this is to say that you can't get into trouble if your plants aren't getting enough sun and temperatures are high, and then you over-fertilize, but these things are easy to keep track of and compensate for.
Regarding soil moisture, I once grew a crop of the smaller "pie" pumpkins, and as the summer wore on hotter and drier, and the pumpkins matured, the vines declined sharply. It was windy, and under clear skies, it was hard to keep the soil moist. I hauled in some rice hull horse stable bedding, and applied it about 2 inches thick over the "moats" I grew the pumpkins in. That was like magic—the plants perked right up, fresh, new vines sprung vigorously from the bases of the plants, and I got a late crop as well.
Ken
