Thread: Hydroseeding
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Old 12-09-2005, 11:59 PM
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muddstopper muddstopper is offline
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Without looking at the product my first response is that the fertilizer is good only if it contains the nutrients your soil needs first. Only way to find out what your soil needs is by doing a soil test and then developing a blend suitable for your seeding conditions.

After looking at the label a couple of things stand out. One, The K source is muriate of potash, a better choice could be a fertilizer containing sulfate of potash as the k source. Sop contain about half the salt of Mop. This doesn't mean your fertilizer isn't any good, just maybe not as good as it could be. Food for thought, most soils, but not all, in the USA already contain sufficient K in the soil for good plant growth. This K is derived from weathered mica and feldspar. It isn't always readily available to the plants because it is held tightly in acidic and low organic, heavy clay, content soil. Because the K is held so tightly in the soil, the additional K can be beneficial at planting but the additional K can also become bound-up in the soil and not readily available. In sandy soil the K has a tendency to leach from the soil.

Second, the nitrogen is derived from 9.4% Ammoniacal and 5.6 percent Urea. The Urea contains more salt than the Ammonical, again not bad but maybe not as good as it could be. Another point about Urea, as little as 5 lbs Urea per ACRE placed in direct contact with the seed, (cant get much more contact that soaking the seed in a solution of the stuff), has been proven to reduce grain crop yields by as much as 50%. Grass is a grain. The loss occurs because under the right conditions, dry, hot weather, the urea will gas off and actually kill the seed and even newly germinated seed or new shoots of grass. Coated urea, (such as SCU) isn't much better if used in a hydroseeder. The agitation and mixing in water has a tendency to crack or dissolve the coating leaving the seed in direct contact with the urea fertilizer. The gassing off isn't as big a problem on properly irrigated areas since the water helps carry the nitrogen down into the soil. Another point is that with the gassing off, you lose your nitrogen to the air. It is safer to use Urea if you are incorporating it into the soil. The soil will act as a buffer between the urea and seed. Gassing off can still occur but it is usually slower and less harmful to the seed.

As a side note, I have my fertilizer blended according to an average of soil samples taken around my area. My blend is not perfect for every site I seed but it is generally closer than anything I can buy off the shelf. The blend is made using 18/46/0 and 0/0/50 SOP and contain no Urea. the blend is 15/39/7 applied at the rate of 350lbs per acre. I get good germination using this blend and amounts and as Earthworker stated, the new grass responds well to followup fertilizations 3 to 4 weeks after seeding. I mostly seed fescue and other cool season grasses.
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