The house I live in 11 years old. And I know the way land is developed here is, they scrape away the topsoil (to sell it of course) and leave the hard barren stuff behind. Once the houses are built, it's up to the homeowner to put in sod, grass and whatnot, the builder rarely includes any landscaping in the price; and if he does, you know they're going to cut all the corners thay can get away with, and it's not going to be the highest quality installation. So my yard soil, beneath the 2" of sod, is most likely good ole' pure Michigan clay. High in minerals and pretty fertile, but extremely sticky and unmanagable in the spring, and hard as cement in the summer. Which is why I had some fancy high-priced "topsoil/compost blend" delivered from the local garden center to fill my new raised beds this spring. But I knew something was amiss lately when the squash and melons just weren't doing much.Tested my soil yesterday with one of those do-it-yourself kits from L*we's. Checked pH, Nitrogen, Phosporous and Potassium. I knew that the nitrogen was probably on the low side, but I had no idea how low. Apparently too low to even register (the 2nd vial from the left). Not a even a hint of pink in the solution.
On the other hand, phosporus (3rd vial) was definitely high, I wonder if it's too high. Too much phosporus can manifest by inhibiting plant's uptake of other elements (such as zinc) and is exacerbated by higher pH, which I also have. My plants are kind of stunted from low N, but there are some weird symptoms that may be mineral-related, like strange leaf colorations on the beans, and some wirey and deformed growth in the nasturtiums. But high phosporus is generally good for things like corn.
And although I'm not sure if I'm reading the card correctly, potassium (4th vial) seems to be on the high side too. High potassium can interfere with calcium uptake, which may be manifesting in the minor blossom end rot I've seen in my tomatoes. Strange, because I have read that greensand, a high-potassium soil amendment, is often recommended for fruiting tomatoes.
pH is around 8, which was a little surprising (1st vial from the left). Healthy soil should have a pH around 6.5 for optimal microbial environment, from what I've read, which means mine is a little too alkaline. Sulfur or peat moss should fix that.
The general data provided by this quick do-it-yourself test is a good starting point, because now I know that if I just bought a balanced fertilizer (with a N-P-K ratio of 10-10-10) like I had originally planned, I would probably not be boosting the nitrogen enough, and at the same time overdosing on phosporous and potassium. Now I am more motivated to have my soil go through a more complete analysis by a laboratory, through the county extension office. Until then, I'm off to buy some slow-release high-nitrogen pelletized organic fertilizer, and maybe a quick-fix high-nitrogen liquid fertilizer too. Elemental sulfur will wait until fall.
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3 comments:
That's one good Dx from just how your plants aren't producing. Do not O-D them on the nitrogen tho. semaj36@comcast.net
I was wondering if you have to do this every few years as the soil can change back or revert to original state?
Rosey
Thanks, dad!!
Rosey, I think I am going to do this soil test every year now, perhaps twice, as I am the type who hates unknowns. I think if I only use fertilizer to boost the N, the soil will not get any lasting benefit, and would revert back as soon as the crops used it up. I'm going to look into using high-nitrogen cover crops, like alfalfa or buckwheat, between plantings, to naturally (organically?) slowly change and build the soil.
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