Improving Soil (Zone 4 Clay)

Hi all! I just started a backyard orchard. One thing I’m noticing is that my soil (unfortunately, clay) may be impacting things. I noticed the trees started showing signs of overwatering (e.g., red tips on new leaves) so I removed the mulch around the holes and cut back on watering. Now, the clay is cracking, but drying out much quicker.

Anyone have success with improving clay soil? I can’t really dig up the trees and plant on a mound (or can I?) since the trees have all been planted since April. I read in another thread on clay soil that planting tillage radishes or other taproot cover crop may be helpful—anyone have success with this?

Thanks, everyone!

Deep rooted cover crops and topdress with organic material that soil flora can move around.

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Any good suggestions on recommended cover crops?

Daikon radish is probably the best to break into the clay.

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my clay has killed every tree i tried to grow in it. its so dense it barely had and roots tap into the soil and slowly choked itself on its own roots. i learned the hard way. now i plant everything on mounds. they all grow great now. put down cardboard, pound a stake in the middle, put tree down, cover with good draining soil, tamp, tie tree to stake, mulch well and water. welcome to the site by the way. where are you located?

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Well, that’s concerning news. I did amend the 3 foot holes with good compost/top soil—does that change the end result? Also, any opinion on digging up the existing trees and starting over with mounds? Or, would that cause too much shock?

And, thank you for the welcome! Glad to finally find a community that can offer some good perspective as I am flying by the seat of my pants most of the time. I am located in Zone 4 in the Midwest (which is the reason for the clay).

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Trees love clay, they are not quite hot about the mistakes we make when we plant them in clay soils. Just about all of said mistakes revolve around drainage.

Do you have a gentle incline? Rent a backhoe, dig a wide trench 3 feet deep by 3 feet wide in the direction of the slope, fill it with pretty much sand (easy enough to amend later) or from the get-go sand and horse compost. I bet you some horse boarding stable near you has a mountain of the stuff that they are dying to give away. That will drain just fine. Do account for it to sink quite a bit as it settles and the organic material breaks down.

Door number two so you end up with a smaller mountain of clay is to dig your trench 1 foot down, build a mound 2 feet tall.

Door number three is a 3 feet tall mound on top of your clay.

Inn any event, make sure you do not just glaze the native clay when you cut into it, it will make it impenetrable to new roots. Take the time to rough the sides before back filling.

There is always the chance that your trees will decide to stay in the channels of nice dirt. Make them big enough and it won’t matter, or take into account the dwarfing nature of restricted roots when picking your root stocks.

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These are all great suggestions. Thank you! What about if the trees have already been planted?

It depends on how they went in. If they were bareroot trees, you pretty much used the same clay that was in the soil, and you roughed up the sides of the hole so the roots could transition there, they should not suffer from the bath tub effect too much… If they are not that big I would wait for dormancy and then move them to the improved draining area.

It is a huge upfront effort but it will pay back for the life of your orchard. Top either version with a ton of green mulch (sub 2" wood chips) and your tree roots will stay as moist as if they were on a forest floor. If you need to water them it will make it very effective.

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I amended the clay soil with good compost and top soil. I think most of the holes were roughed up, but some were not (I did not read about that concept until half were in).

Sounds like I have some work when they go dormant.

if you added compost and such id wait to see if they rebound. being in ground as long as they have i wouldnt try digging them out.

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They all seem to be doing great. Most have 8” of new growth so far (for reference, most trees are 6’-8’ tall). The drainage issue seems to be somewhat resolved by removing the mulch and letting things dry. Although, I still do fear the bathtub effect.

once it dries a little more, replace the mulch and only water deeply once every 3 days if you dont have rain. with the added soil/ compost in there they should have the resources to push into the clay. i didnt do that when i planted mine inground. just used the native clay. i did roughen the edges of the hole but it didnt make a difference.

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I have been doing a deep watering (through a hole in a 5 gallon bucket) every Sunday. Sounds like I should increase that somewhat.

Also, thanks for the insight! I feel like I am over my head half the time, so I really do sincerely appreciate your (and everyone else’s) perspective on things.

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thats what we all come on here for. good luck!

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I’ve moved trees that have been in the ground 2 seasons so it can be done it’s comes down to how hard you want to work at it. I would not transplant until dormancy if you do. I’ve also poked holes around my trees with a pitch fork and spread peat moss to fill in the holes.

I actually just purchased a bag of moss for this reason. Do you think it helped?

I can’t say for sure but it seems like a way to get some organic matter in the clay outside of your amended soil.

@HunterHomestead

It matters more what the type of trees are as much as anything else. Cherries die quickly if they get their feet wet. Pears can tolerate some water.

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Would mixing top soil or garden soil from a box store help the heavy clay situation