Fall organics application and info. for alkaline soil

12 years ago

Thanks, Krista, for advising me to apply manure and slow-released organic fertilizers in the fall, before the ground freezes. I found data from Canadian wheat agriculture that supports Krista's good tip. Optimal pH of wheat is 6.5, same as roses.

The site is: http://www.agricocanada.com : "It is easier to apply Nitrogen on frozen ground early so that we do not miss this stage due to wet soils. The amount of Nitrogen to apply at this time would be 35 to 40% of the total Nitrogen required for this crop. If all of the Nitrogen is applied to the crop after the tillering stage it will only promote vegetative growth and might increase disease pressure."

Some info. from Colorado State to help people like me growing roses in alkaline soil with free lime: "Soils with a pH of 7.5 and higher typically have a high calcium concentration that binds P as calcium-phosphate creating an insoluble compound that is not available to plants. Therefore, it is necessary to amend agricultural soils with available forms of P.

Apply manure in the fall. It takes 3-6 months for phosphorus to be available. Rock phosphate is not readily available for plant use in soils with pH above 7. For this to be available, the acidity of the soil solution must dissolve the Phosphorus. Bone meal should be used ONLY when the pH is below 7... The major problem with high pH is iron chlorosis. Soils with a pH above 7.3 and/or with free lime (calcium carbonate) can be amended with acid peat moss at the rate of one to two cubic feet per plant. This only last for a few years. To test for free lime, place a tablespoon of dry soil in a cup. Moisten it with vinegar. If the soil-vinegar mix bubbles, the soil has free lime."

The Florida State U. Extension stated that lowering pH with sulphur only lasts for 1 year. Another site added that lowering pH with sulphur or raising it with lime only lasts for 1 year. Which means I have to make frequent trips to Starbucks for acidic coffee grounds for my white pines, azaleas, rhododendrons, and roses.

Plants like wheat and roses with optimal pH of 6.5 can't extract phosphorus from soil as well as plants with higher pH preference. The Aussie achieved success with increasing wheat yield through applying liquid phosphorus, along with other elements. Rose growers also reported success with alfalfa tea.

At first I blamed my alkaline soil on lime stones (calcium carbonate). Then I had my soil tested professionally by EarthCo. with the result of 7.7 pH, super-high magnesium, but adequate in calcium. When I tested pH of various stuff using red cabbage juice, the control cabbage color didn't change a bit with calcium citrate, but shot way up to the alkaline zone when tested with magnesium oxide (even more green than baking soda).

I once read a book by a gastroenterologist, M.D., who recommends people to take a magnesium supplement rather than Tums for acid stomach and heartburn. It finally made sense when I tested the pH of mangesium supplement (mixed in distilled water) with fish-tank litmus paper, again, it shot way up past 8.4 alkaline zone.

Here is a link that might be useful: Phosphorus and alkaline calcareous soil

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Comments (3)

Krista_5NY
12 years ago
last modified: 9 years ago
Hi Strawberryhill. Yes, I have topdressed in the autumn as well as spring and summer. I'm so busy with spring planting and pruning that I find it convenient to spruce up the rose beds in autumn. I'll be interested to hear if other folks do this as well.
ingrid_vc so. CA zone 9
12 years ago
last modified: 9 years ago
I've thought about using alfalfa meal in the fall since the roses are still blooming for the most part, and it would be nice to give them an extra boost. It rarely freezes here, mostly in January and February, and only for short periods. I wonder whether fertilizing now is a good idea, a bad idea or somewhere in between.

Ingrid
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strawchicago z5
Original Author
12 years ago
last modified: 9 years ago
Hi Krista - your roses look fabulous so it must be OK. I also wonder if there are others with success in fall topping.

Hi Ingrid: The website with a table on organics reported 1 to 3 months for alfalfa meal to decompose. I threw alfalfa meal on my 8' tall white pine in July - we have lots of rain, now there's still some left-over crust. It didn't do any good for my white pine (still yellowish, NOT lush) - last year blood meal worked better (this has iron).

Roseseek (Kim) is right about Nitrogen moves with water, versus phosphorus and potassium stay put where it's applied. Here's what EarthCo (the soil-testing company) has to say about phosphorus, taken from their booklet: "Phosphorus doesn't move far from where it was first applied... it must be worked into the roots zone. Phosphorus is locked up when the soil pH is too high or too low ... this must be adjusted PRIOR to its application."

Alfalfa tea does both: acidifying the water, and releasing the phosphorus after 1 week of stinky fermentation. That's why the Aussie reported 15% to 30% increase in wheat yield through phosphorus in a liquid, versus ineffective results with granular phosphorus.

When I tested with red cabbage extract, alfalfa meal came out more reddish and more acidic than peat moss at pH of 4. What I like about alfalfa tea is that you don't burn roots with concentrated acid. Diluted with water, it is a mild acid which unlocks phosphorus in your soil, and moves its own released phosphorus to plant roots deep below the soil.

When I used the accurate litmus paper for fish tank, my water pH is very alkaline at 8. It's best to water roses that prefer a pH of 6.5 by bringing down the pH of alkaline tap water with alfalfa meal, or making a basin around the soil and filled with even more acidic coffee grounds.

I have wasted enough money on worthless soil-test kits from stores - so here's my conclusions to save others wasted time & money: 1) the most accurate pH test for your water is litmus paper for fish tank.

2) The most accurate pH test to compare many substances is to chop red cabbage small, boil in distilled water, and mix your soil in when the water is hot (it dissolves calcium and magnesium better). Then compare the solution above your soil with other solutions: miracle Gro potting soil(pH of 6.5), vinegar (2.4 to 3.4), baking soda (pH of 9), and peat moss (pH of 4).

Soil deficiency in magnesium is rare except in sandy soil. About 1/3 of soil are deficient in potassium, so banana peels are always safe for fall dressing. I don't like manure dressing since it's high in salt. I am testing the coffee grounds dressing so see if the growth in the spring is green.

Below is another guy's rating on many soil test kits from stores, including Rapid-test. His conclusion is the same as mine: they are all worthless, a waste of money. The Canadians recommend nitrate as the best source for fall dressing for wheat crops (nitrate works best in cold weather).

Here is a link that might be useful: Wayne's rating of soil-test kits.