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Reasons for testing pH of bagged soils: lousy performance

strawchicago z5
12 years ago

I have good reasons for testing the pH of bagged soils after lousy performance of at least 25 bags this summer. My neighbor gave me lots of free annuals from his nursery, so I created a bed for them. Since it's at the low end of the garden, I topped it off with 10 bags of Scott's Premium topsoil with peat moss, and 15 bags of EarthGro soil from HomeDepo.

I planted a Japanese Maple tree in the 10 bags Scott's Premium topsoil. The leaves turned brownish at the edge. It's the same lousy performance on alkaline soil that I saw with trees planted on top of lime stones. It's the same symptoms that I saw on the Bloodgood Japanese Maple that died on me 10 years ago, when I foolishly put 1 bag of very alkaline mushroom compost (pH of at least 10) in the hole. My estimate of Scott's top soil pH is at least 8 compared to my alkaline soil (tested at 7.7 by EarthCo) - it's definitely more green when tested in red cabbage juice.

After 7 months, the Japanese maple tree barely survived on Scott's top soil, and did not sprout any new leaf. Japanese maples prefer slightly acidic to neutral. I have two other 12 years old Japanese maples that are big and healthy, planted in native clay soil amended with peat moss.

The EarthGro top soil was even more alkaline when tested in red cabbage juice. My estimate: 8.5 pH. My hubby bought 2 peonies for me in April. I planted the red one with 2 bags of EarthGro top soil. The leaves sprouted, but kept turning brownish at the edges. It went completely brownish, then died on me. At first I blamed it on the rain, but when I dug it up, that spot is well-drained. Two feet away is another peony that my neighbor gave me, planted in native soil, but very green and healthy. In the same area, I planted a 3rd peony, on native soil mixed with 1/2 bag of EarthGro, leaves are brownish at the edge, but haven't died on me. The Moo cow manure from HomeDepo is the most alkaline, more green than baking soda (pH of 9). Others report the same, it's either really acidic pH of 4 to 5 for stinky bagged cow manure, or really high 9 to 10 for manure treated with lime to deodorize.

pH range for peony is 6.0 to 8.0 - and pH range for roses is 6.0 to 7.5. I will order a big pile of dirt for the 3 new gardens I made for 20 more roses next year, plus the raised veges and tomato beds. I'll test the dirt before buying it with 3 small bottles of red cabbage juice boiled in distilled water. One is for MiracleGro potting soil (pH of 6 to 6.5, depending on how much peat moss is in your sample), one is for my native soil (pH of 7.7), and one is for the dirt to be purchased. After doing red cabbage pH test 4 times on at least 15 samples, I am getting better at judging pH by the color.

If you want to be really accurate about your pH, here's some good info. from the soil forum: � Posted by ericwi Dane County WI (My Page) on Fri, Jun 11, 10 at 11:10

I have to test our soil for pH, routinely, every summer. We grow blueberries, and our soil is calciferous, with a pH around 7.6. It gets amended with compost made from shredded leaves and agricultural sulfur. Sometimes I have to lower the pH of our tap water with vinegar, before watering the blueberry shrubs. But you can kill a blueberry shrub with too much acid, so getting the pH right is essential. I used to use a small pH meter, carefully calibrated with solutions of known pH, to test soil samples. Now I am using indicator dye solutions, which are inexpensive, and don't require calibration. Bromothymol-blue will turn blue at pH=7.6, and yellow at pH=6.0. Bromocresol-purple is purple at pH=6.8, and yellow at pH=5.2. Bromocresol-green is blue at pH=5.4, and yellow at pH=3.8. You dig up a small sample of soil, about one tablespoon, and drench the sample with distilled water. The excess water is poured off, and filtered through a coffee filter or something similar, and the filtrate is what gets tested for pH. Each indicator dye costs around 2 dollars, for one fluid ounce, enough to do about 100 soil tests. There are several scientific supply houses that sell the appropriate dye solutions, through the mail. Elemental Scientific and HMS Beagle are two that I know.

**** Here's a link that reports on high pH of bagged horse manure (pH 8.21) and very low pH of cow manure (pH of 4).

Here is a link that might be useful: Failed performance of cow and horse manure

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