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Friday - July 04, 2008

From: Austin, TX
Region: Southwest
Topic: Non-Natives, Turf, Grasses or Grass-like
Title: Source for nitrates and phosphorus (P205) for lawn care
Answered by: Nan Hampton, Sean Watson, Julie Krosley


I recently supplied soil samples from my back yard to my local extension here in Austin. I have a hybrid Bermuda turf grass (TIF 419) that has had its share of ups and downs, and wanted to assess the soil pH. They advised me to apply 1 lb. of Nitrate (N) per 1,000 sq.ft. every 6-8 weeks, and also to apply 2.3 lbs. of Phosphorus (P205) per 1,000 sq.ft. because the Phosphorus levels were very low. Where do I get pure Nitrate and pure Phosphorus? Home Depot doesn't sell it that way .. only in typical fertilizer bags where these elements are mixed percentages.


So far, I haven't found anyone at the Wildflower Center who has ever bought and used the two products separately—they've always used a fertilizer mixture. It is possible that you could find these two, the nitrates and phosphorus (P205), at an agricultural supply store or at a landscape supply company such as John Deere Landscapes (with two locations in Austin). This company has a large number of fertilizer products and perhaps, if they don't have the pure products, you could find one with the correct ratio of nitrates to phosphorus. You need to realize that many of the fertilizer mixtures have been constituted to provide a gradual release of the chemicals and the pure products aren't likely going to do that—you risk causing chemical burns to your grass with the pure products. However, if you are intent on getting the pure products, you might contact the extension agent again since they recommended these products and probably know a source for them.

Alternatively, a couple of the members of our horticultural staff have suggested that you visit The Natural Gardener in Austin and take your soil analysis and recommendations with you. They might be able to offer organic substitutes for your lawn. Our nursery manager suggested that you could try topdressing with a compost/bone meal mixture to increase both nitrates and phosphorus. Compost does wonders for turf grass if applied liberally twice a year. Compost usually has a 1-1-1 ratio (N-P-K....a finished compost has little ammonium since it has been broken down into nitrate, thus, most nitrogen in compost is readily available for uptake by plants). Adding bone meal would increase the ratio of phosphorous to nitrate.

If your bermuda grass lawn continues to be a problem, we hope you will consider replacing it with a native lawn using Bouteloua dactyloides (buffalograss) in the sunny areas and perhaps a sedge lawn, groundcover, or wildflowers in shady areas.


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