Fertilizers That Help Raise pH
There are acid-loving and alkalinity-loving plants. Knowing your soil's pH helps you figure out which kind to grow. But if you want to change your soil's acidic nature to grow something that prefers a higher pH, such as geraniums, or if your soil is so acidic it can't support most plant life, there are a few amendments that raise soil pH. Does this Spark an idea?
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Nitrate-Based Fertilizers
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A nitrate-based fertilizer, such as 13-2-13 or 15-5-15, might raise your soil's pH. But the University of New Hampshire Cooperative Extension warns that if a week after applying one of these fertilizers the ground still has low pH, a new product should be used--especially if you have plants in the geranium family in your garden. Those plants can't access the nutrients in the soil if the pH is below 6.0, and become stressed.
Potassium Bicarbonate
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Potassium bicarbonate is a water-soluble alkaline that helps to balance acidity in the soil. If you've tried a nitrate-based fertilizer without success, potassium bicarbonate might make a difference. Potassium bicarbonate, however, damages foliage. This chemical is most beneficial if you make drenches in the soil and put it in them. Irrigation then will drive the potassium bicarbonate into the ground. But once alkaline and acidic substances come together, salt is formed. So, using potassium bicarbonate to raise pH also may require leaching the soil later to remove excess salt.
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Hardwood Ashes
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Hardwood ashes have calcium, which raises pH in soil. But ashes pose a couple of problems. If you use too much of it, your plants will be unable to access the magnesium and calcium available in the ground and will stop thriving. Also, handling the ashes' fine particles could aggravate respiratory problems or create a new one. An advantage of using them is that you can get them for free if you have a fireplace. But you may want to use a mask and amend your soil on a day when the air is still.
Hydrated Lime
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When you mix calcium oxide with water, you get hydrated lime, a white powder that's usually used to raise the pH only in very heavy clay. Because the hydrated lime formula is so strong, there's actually the potential for it to ruin the soil for plants while trying to fix it. In fact, once its particles are released into the soil, they can burn any roots they come in contact with, killing your plants. Hydrated lime also is caustic to skin. Wear gloves if you use it.
Agricultural Lime
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Agricultural lime is a blend of calcium carbonate, magnesium carbonate and several other chemicals. Once agricultural lime particles enter the soil and are activated by water irrigation, they consume the existing acid. But agricultural lime works slowly, taking one year or so to raise soil pH.
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References
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