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soil amendment question [bad clay soils]

11 years ago

Hello to all,

It was highly recommended that I amend my clay "soil" w two diff products:
dried molasses and cotton-seed-meal. The term "soil" here is really an insult.
I this part of TX, the top 4-5 feet can be made of a very nasty clay or
"gumbo-soil" as it's called.

We had our backyard landscaped, and the amt of topsoil used to prepare the
beds by landscaper was way less than I thought. a couple inches of mulch were
applied on the top after the plants were installed, so I could not see how much
soil was used.

we had a lot of rain in winter, May & June, now 35+ days of ZERO rain and
the heat is 100+, so we are watering a lot but this crappy soil is getting real
hard. It was recommended to mix a combination of dried molasses and c-seed meal
and then turn or mix into top 2-4 inches. I did so and watered heavily. The
next evening after sun all day, it had a pretty strong smell, not pleasant. Is
this common of this amendment process? Has anyone done this before?

I saw the results of another process like this and the plants just really
took off big-time. Cannot get a hold of those folks bc they are gone for
summer, so thought I would post it here.

Comments (8)

  • 11 years ago

    Cottonseed meal is basically an organic fertilizer, NPK about 6-2-1. Depending on how much you added, you might be getting a flush of nitrogen as it decomposes. If there is not enough air down in the soil it can create odors for a bit. The molasses could contribute to that, it's like rocket fuel for microbes.

    I have never used either product and don't know how much molasses costs, but I would guess there are plenty of other potentially cheaper ways to amend soil, especially over the long term. Adding compost will improve soil texture, organic matter content and add NPK as well. You might repeat this exercise with compost once or twice a year (spring and fall) for several years to get some organic matter into the soil and get things started. After that, you can go the slow route by putting down degradable mulches - even compost, covered with shredded leaves, grass clippings, wood chips etc. Over time the soil will improve dramatically.

  • 11 years ago

    Thank you, I appreciate your follow-up.

    This same regiment was performed at another clay-soil vicinity when friends moved into a newly build house, and newly landscaped too. As we know, it all starts w the soil.

    Their plants were just not making a lot of progress and compared to other homes that had 1.5-2yrs of established growth, there plants really looked bad. They basically loaded up the cotton seed meal and dried molasses by the buckets, worked it in and watered well. Over the next 2-3 months. their plants looked better than the established yards and extremely healthy. Seeing is believing and neither one of them are major gardeners.

    Again, appreciate your feedback.

  • 11 years ago

    Cottonseed meal stinks. Wet meal stinks worse. Both it and the molasses are fertilizers and won't do much for permanent spoil changes.


    Apply as much organic matter (compost whatever you can find and pile it on) to improve the soil texture and drainage.

  • 11 years ago
    last modified: 11 years ago

    Organic matter helps to loosen soil. Also texture amendments help too.

    I don't have your soil so I don't know how this would work there in Texas, but it works wonderfully well here with my clay loam and silty clay loam. People talk about having clay soil. Nearly all soil that isn't totally sand has these three soil ingredients: sand, silt, and clay...even yours likely too.

    I added 3 inches of medium/coarse sand and 4 inches of local sphagnum peat moss. I forked and mixed it all into the top 7 inches or so of my topsoil. I then deeply tilled it it...instant loose soil. Of course I added a fair amount of compost and organic matter.

    Your mileage my differ, but likely would be helpful.

  • 11 years ago
    last modified: 11 years ago

    we had a pool built and summer kitchen/fireplace added in all of 2014. Summer kitchen slab and fireplace has many 10ft bell-bottom piers. A lot of heavy equipment was used so he soil was compacted. It also rained a lot. They dug 2 - 2.5ft down for PVC piping, then electrical, water, etc. Many times they could dig trench and it would keep perfect 90 degree form bc the clay was so thick. You could make adobe bricks from this stuff. Trying to work anything into this is virtually impossible, now that its getting hot and dry [watering included]

    The landscaper built some beds up, but a lot of it was scraped some, little top soil, plants installed and then 2-3 inches of mulch. I did work-in the mulch some. We basically poured the dried the Molasses on first, then the CS-Meal, then I took a pitch-fork and pushed into the ground and turned over the Mol & CSM and mixe/covered w mulch. Some of the mulch had "thatched" and some was breaking down some. this should help provide some solid amendments while the CSM replenishes the N as the mulch breaks down and the Mol as a basis for promoting microbial production.

    When we had a 9-11" rain [almost a foot of rain} in June one night, about 250-300 earth worms were pulled from the pool the next morning. I wish I could have saved them. I guess the soil has some redeeming qualities for them to be in the soil, but it's hard to see it.

    Thanks again.

  • 11 years ago

    If you can once get things like sand, peat moss, and organic matter mixed into the soil, these particles will help keep your soil from compacting into a hard solid mass [mess].,..they will separate clay from clay.

  • 11 years ago

    this is great website and I immensely appreciate everyone's help. There's a place called "Living Earth" in Houston and they sell all kinds of organic matter by the truckloads...it's time to order one and have wheel-barrow party at the house w some favors cashed-in...

    Kim, based on your soil tests, I have a LONG WAY to go..I will do the tests this weekend and post back...I have to leave town from Thur to Sun, then I'll get moving. Thanks