Difficult soil.. prep?

[RickF]

Hi all... I'm in the high desert of California (northern LA county) and once I dig below about 6-8" of what I assume the home builder put in place 30+ years ago, I hit really hard "soil" -- I use that term loosely. I think its probably clay primarily. Eventually this area where I'm digging will be buried with chips (ala back-to-eden methods) that I had delivered today but its not ready yet.

For now I'm digging two holes for a couple of apple trees -- one Fuji and a Gravenstein. I want to make sure the soil is about as good as possible. The holes I'm digging are at least double-wide and double-deep per the trees root balls. I'm planning on putting a mix of Amend, peat moss, and some other garden soil I've got sitting around. Is there something that can be added at the bottom of the holes to, over time, soften up the hard clay soil? I put water in the holes to a depth of about 6" deep for 2 days and it did go down by perhaps 2-3" but 2-4" remained. I dug into the holes with the shovel and one hole I dug down perhaps 2-3" and it was bone dry (after I removed the water thru shoveling). Thoughts?

 

[dickiebird]

Move!!!

THANX RICH

 

[Collector]

You might be dealing with caliche soil,which I have no experience trying to grow anything in. If so you may want to go to a local nursery and ask what might be done to help.

 

[RickF]

You might be dealing with caliche soil

Thanks for that Collector! I did find some references to having that in the valley in which I live. I did find this reference that seems to give some possible options including the use of elemental sulfur to the soil to help with iron availability and to improve drainage. I found the following quote from another site regarding elemental sulfur :

Elemental sulfur (S) is an acid-based material that is transformed into sulfuric acid by soil microorganisms; this in turn reacts with soil carbonates as shown in the reaction above. A potential disadvantage of using S is its slow reaction time. In warm, moist soils, four to six weeks may be required for the complete transformation of S to sulfuric acid; in cold or dry soils this conversion will take longer.

This blog post had some great suggestions too... I just went out and poured some vinegar into the two holes and sure enough they started fizzing like a leaky car battery does when you apply wet baking soda to it. Too bad I can't put a bunch of battery acid down in the hole to eat through it. lol

I also found the following quote from this site that was particularly interesting :

You want to buy a 50 lb bag +, depending on the size of garden, of Cal CM Plus made by the Art Wilson Co. This is an organic product. This is sold as Soil Buster at Lowe's and Home Depot in rather small bags last I checked. This will break up clay. Plus it unlocks the nutrients that get locked up in clay. You can read about it at www.calcmplus.com. If you have caliche, you likely have red clay soil. I just spread the Cal CM plus like a pelleted fertilizer on my backyard. I've done two deep waterings since, my plants are looking a brighter green, I don't expect the soil to loosen significantly until it has gone through several more deep waterings. Ideally, adding this product while creating a garden bed, as your turning over & tilling the soil is ideal.

I can buy a bag of the above stuff at a local irrigation supplier for about $15-$20 for 50lbs.

Interestingly enough someone on the above houzz site does suggest using pool acid to eat through it as I alluded to above.. To correct it though, its not pool acid but sulfuric acid.

And here concludes your tour de solutions to the soil known as Caliche... Thanks for the pointers!!

 

[flowerbug]

what you are doing is basically digging a hole where water will sit and not likely be all that great for the trees. what you need to do, which of course is a lot more work is to trench to break up that hard pan layer outwards in several directions (like a star pattern) and then fill the trenches with decent topsoil. no matter what you use to amend with over the longer term the soil always reverts to basic type. so your long term approach to such soils is to make sure the drainage is good and then grow things which in the end will give you weak humic acids. you can use elemental sulphur or gypsum (anyone selling you that for $15-20 a 50lb bag is a ripoff artist) to make that faster, but you sure won't want to plant into those until after the chemical reactions are toned down.

it's really never a great idea to do anything with living plants in an area if you are going to shift the soil community/chemistry to a large degree.

in areas where they have high alkaline soil the more gradual approach is to do some light trenching so the tree roots will have someplace to go and anchor the tree, but to otherwise let it do it's own thing. the roots give off acids and will head down for moisture if there is any. but you are pretty much just mounding up on top of the poor subsoil so there isn't a drainage issue. you don't want a puddle. mulch heavy, drip irrigation to keep it alive between rain events. when it does rain if it isn't very much give it a good soaking to encourage the roots to go down further and to add light acidifier amendments with your mulch. like sprinkling some sulphur on there when you add the mulch. but otherwise encourage your organic decomposers to do the soil mixing for you. worms will do ok in clay if they have enough food, moisture and mulch to protect them from the heat.

what you don't mention is if the apple trees are on dwarf root stock or not and hopefully they are suited to the climate. i rarely hear of people having very good luck with growing apples in southern climates unless they happen to be up in the hills where it is cooler long enough in the off season, but perhaps you have selected varieties which will do ok...

good luck.

 

[Nyboy]

Apple trees need great drainage, you need to plant yours on mounds. I have heavy clay that drains slow only apple that do well here are crab apples.

 

[RickF]

I'm very tempted to build a raised bed/box for each -- perhaps about 18"-24" tall above the ground and build drains in all 4 sides of the box to allow drainage that way... I should also note that I'd probably build the box extra large -- instead of it being perhaps 2' on each side, perhaps it needs to be at least 4' on each side to allow for adequate root area aside from whatever vertical capacity exists..

 

[RickF]

apparently I missed a post or two in the middle. Doh.. Anyway, the apples I've chosen are fine for this climate. Considering I'm in the northern corner of Los Angeles county, we had plenty of nights in the mid to high 20's this year and tons of hours in the low 30s. Regardless, I am considering moving the tree locations to another place in the yard that is already raised by a good 2-3 feet above grade and the planter "box" (cinderblock) has plenty of lateral room should they need it -- it's about 6' x 20' and has planting space on either side that is also raised. You may be correct about the cost of said 50lb bags of stuff -- keep in mind that it was very late when I posted that here (midnight) and I couldn't check any places to see pricing aside from a quick net search.. I will be doing some excavating in said planter to see how things look beneath the "hood"..

 

[Nyboy]

I buy truck loads rather then multi bags much cheaper. Call nursery and ask about truck load delievery

 

[majorcatfish]

sounds like you need a tractor with a turning plow to break up your soil....or a really good rear tine tiller.. i do wish you the best...