I added sand to my clay soil... should I replant?

[PhilippineExpat]

My garden has clay soil so I decided to amend it to give it better drainage when I planted a couple of young foxtail palms. When I planted the foxtails (2 days ago), I filled in the holes with a mix of clay soil from the hole, vermicast, and sand. They were in about equal 1/3 parts. I added the sand thinking it would help with drainage, but I just learned that sand and clay will make a cement-like substance. Should I take out the foxtails, remove the soil, then replant them without any sandy soil? Or should I just leave them be?

Edited March 7, 2020 by PhilippineExpat

[atlantisrising]

I'm not sure about the mix making a cement, never heard of that. In my experience dealing with the swampy claylike muck that passes for topsoil is South FL, the more sand the better. Sometimes more sand than soil. It's the sand that gives you drainage.

[rprimbs]

Sand and clay make cement?  I have a Bachelors degree in geology.  The way that clay holds water is very simple.  It has to do with amount of surface area that water can stick to.  Let's say you have a large boulder.  The only surface for water to stick to is the outside.  If you break it in half then you have new surfaces for the water to stick to.  If you break it again then you have more surfaces for water to stick to.  As the pieces get smaller and smaller there is more surface area for water to stick to.

So "clay" just refers to very small particles of rock.  I have clay soil.  My soil is called "DG" -- decomposed granite.  It breaks down into very small particles.  I don't know the mineral makeup of your soil but I would question the assumption that adding larger particles to the soil would turn it to cement.  I have added the same sorts of amendments, as you did, to my soil to grow vegetables and it has worked great.

[Darold Petty]

Anecdotal advice given to me suggests that sand added to clay will not yield improved drainage.  Organic compost is the best choice.

  Disclaimer.... I have very sandy soil and thus no direct experience with this problem.  For my garden,  increased nutrition and water retention is the goal, and organic matter is again the solution.  

[OC2Texaspalmlvr]

5 minutes ago, Darold Petty said:

Anecdotal advice given to me suggests that sand added to clay will not yield improved drainage.  Organic compost is the best choice.

  Disclaimer.... I have very sandy soil and thus no direct experience with this problem.  For my garden,  increased nutrition and water retention is the goal, and organic matter is again the solution.  

In another thread someone I cant mber who, also cautioned adding just a bit of sand to clay doesnt help with drainage. Mass quantities of sand has to be introduced to really help. Organic material will help a bunch. Not sure if vermicast is the same as vermiculite which actually helps with water retention. Doesnt sound like a great way to amend your soil @PhilippineExpat. Fighting really bad clay soil some of us, mound plant to help keep roots a lil dryer not sure how bad your clay is tho. How you dig your hole prolly makes the biggest difference I learned the hard way. Dont dig a really deep hole which just makes a fish bowl for your palms roots =/ Hope this helps I honestly dont believe you need to replant unless you have really bad clay soil. 

[Silas_Sancona]

When it comes to adding sand to clay-ey soil, i think the benefit(s) of doing so depends on the grain size of the sand itself.. Having used sand myself both for soil mixes and mixing in w/ native soil, small/ fine-grained sand, like what would be found along many beaches in California, Texas ( at least where i'd collected some while in the area ), and areas of Florida would likely retain too much water, especially when added to heavy clay and cause more issues unless perhaps the sand made up 80+% of the soil composition..

On the other hand, large -(er) grained or "River" sand, like what you find along many rivers here in AZ, Texas,  ..or rinsed Decomp. Granite. could work out well to help improve drainage, especially when mixed w/ organics like compost and then added into the native soil. That stuff ( the river sand ) drains real well and has very little silt in it.

As far as Vermicast, = worm castings ( worm poop, lol ) and can help improve soil, but eventually breaks down into finer particulate. Would never add Vermiculite to clay soil.. Bad stuff as it is, will just make the soil retain more water.

[joe_OC]

You want to add organics and gypsum, not sand.  Your soil can be improved, but you need patience.  It takes some time to see the results.

[sonoranfans]

Organics are needed but they decompose, you have to keep adding them annually.  I had heavy clay soil in arizona and using 1/3 (paver) sand, some organics and pearlite in some places worked well.   the perlite reduces density prevents compaction.  The sand also helps prevent the clay from re-compacting, so water can get through.   But I dug deep to ensure the water had a way out in a number of areas.  If you have compacted clay underneath, it will still dry cycle slowly.  Applying sulfur pellets, sodium dodecyl sulphate(surfactant) and humic acid helped to shift the clay soil drainage as well, it breaks up some of that clay.   But sand alone doesnt ensure drainage: if its in a clay pot with no drains(your yard?) then it wont be drying out anytime soon.

[PhilippineExpat]

Thanks for the responses everyone! Sounds like I definitely made the wrong call adding sand =/ It's frustrating because I have rice hull I could've added instead. Oh well, at least I only did this for a couple of palms. Well, I also did it for my saribus rotundifolius but apparently it loves moisture, so I'm not worried about it. Maybe I'll leave them be as an experiment and see how they compare with my manila palms which I planted with rice hull and no sand. We have 6 months of drought here every year, so maybe it's a blessing in disguise lol. We'll see how rainy season goes, though.

 

7 hours ago, OC2Texaspalmlvr said:

In another thread someone I cant mber who, also cautioned adding just a bit of sand to clay doesnt help with drainage. Mass quantities of sand has to be introduced to really help. Organic material will help a bunch. Not sure if vermicast is the same as vermiculite which actually helps with water retention. Doesnt sound like a great way to amend your soil @PhilippineExpat. Fighting really bad clay soil some of us, mound plant to help keep roots a lil dryer not sure how bad your clay is tho. How you dig your hole prolly makes the biggest difference I learned the hard way. Dont dig a really deep hole which just makes a fish bowl for your palms roots =/ Hope this helps I honestly dont believe you need to replant unless you have really bad clay soil. 

I read the same thing about digging a palm hole yesterday after I started to research it a bit. It seems like you want a hole just as big as the root ball and no bigger. Also, I found a brief article by a soil researcher yesterday who said you need to make soil at least 50% of it sand to develop sandy soil properties. I definitely did not add that much. Oh well, live and learn. 

Edited March 7, 2020 by PhilippineExpat

[redbeard917]

For vegetable gardens, people add large amounts of compost, and then run a tiller over the area, which results in loosened soil with organic matter mixed in. I would think palms would like being planted in that too.

[PhilippineExpat]

7 minutes ago, redbeard917 said:

For vegetable gardens, people add large amounts of compost, and then run a tiller over the area, which results in loosened soil with organic matter mixed in. I would think palms would like being planted in that too.

That's actually how I approached this. I read that veggies love it when soil is 1/3 vermicast which is why I used that ratio. The soil is definitely super nutrient rich. I hope that makes up for the less than stellar drainage. I'm also hoping that the sand I added won't matter too much once the roots grow beyond the hole I dug. I guess only time will be able to tell. 

[branislav]

Tillering destroys the structure of the soil. It's very bad practice as recent research shows despite being popular. It comes from agriculture where they want to grow many crops fast and use a lot of fertilizer. It's really not suitable for home gardening. 

Adding sand to clay won't turn your soil into cement or anything like it. It just won't do anything unless you put massive quantities of coarse sand.  And then it still won't work once the roots try to get out of the area you amended. Plus the part where the amended soil meets your native soil becomes water repellent (since the density is different) so your amended area will actually not drain all that well. 

As others have said here, mulch and wait. There is no shortcut. The good thing about clay is that it also holds more nutrients so you won't need fertilizers. Just don't overwater. I know many people here are growing very happy palms in clay. 

[PhilippineExpat]

3 hours ago, branislav said:

Tillering destroys the structure of the soil. It's very bad practice as recent research shows despite being popular. It comes from agriculture where they want to grow many crops fast and use a lot of fertilizer. It's really not suitable for home gardening. 

Adding sand to clay won't turn your soil into cement or anything like it. It just won't do anything unless you put massive quantities of coarse sand.  And then it still won't work once the roots try to get out of the area you amended. Plus the part where the amended soil meets your native soil becomes water repellent (since the density is different) so your amended area will actually not drain all that well. 

As others have said here, mulch and wait. There is no shortcut. The good thing about clay is that it also holds more nutrients so you won't need fertilizers. Just don't overwater. I know many people here are growing very happy palms in clay. 

The more I learn about soil the more I see the advice to not mess with it. For all of my future palms, I plan to make the hole as small as possible and then work in some vermicast on the top and add mulch if the ground is exposed to the sun. I'm relieved to hear a few of you say the sand and clay mixture won't become hard, but I still see it was a bad decision. 

As for the overwatering bit, do you think I still need to water new transplants every day for the first week or 2? My thinking is, if I don't mess with the root ball and the soil is clay and stays moist for a few days at a time, then maybe daily watering is too much. 

[GottmitAlex]

Unless your palm is a Coconut, don't add or replace your current soil with sand. Period. 

[Tyrone]

If you have pure clay and you want to add sand, you need to make the sand around 80-90% of the soil profile or the clay will just clog up the sand particles. Adding organics is far better as others have mentioned. Clay if you can aerate it and open it up is actually a great substance for holding onto moisture and nutrients. Adding organics makes the clay open up. Eventually you’ll have good soil. All the best improving your soil.

[sonoranfans]

In order for mulch to work in breaking up clay soil there has to be some humidity to keep it damp so the microbes can work on it.  When I lived in arizona, I found that to be difficult, the top mulch dried out and blew away mostly and if I kept watering the deeper soil wouldnt dry cycle and I'd get root rot.  I always lanted 1/3's sand organic clay for an oversize plan ting hole(3x rootball). work organic matter into the soil.  The poor function of mulch in the desert is one of the reasons they use granite rock as a surface dressing out west, it keeps the soil under it moist, a lot better than mulch, and reduces the moisture gradient in depth so you can dry cycle more uniformly.  Here in florida, mulching works very well as the sandy soil is easy for the mulch to work its way into and it supplies critical cation exchnge capacity which is ~zero in sand.  Clay also works well here and I do have some at depth 2-3' in some places.  With clay you get nice cation exchange but you also get a variety of macrostructural clay some of which can be impenetrable to water and roots.  They use clays to line storage ponds and prevent them from leaking into the water table but most gardeners dont have that kind of clay.  I had variable clay compaction in my yard in Az to start, so I researched how to break it up.  Gypsum works well for low calcium soils, but calcerous soils are better approached with elemental sulfur which breaks down slowly(microbiological) to sulfuric acid and subsequently forms gypsum(CaSO4) by reacting with the excess calcium in calcerous soil.  Gymsum is calcium sulfate(CaSO4) so it doesnt break down high calcium clay, but elemental sulfur biodegrades and reacts with Ca in the clay to form gypsum(CaSO4).  From what I have read, you need to till in the top 3-4" and I did this with good drainage improvements after a couple years(2-3) and two applications.  Adding in humic acid also helps remove some of the Na, Ca in alkaline soils once the soil can drain.  The reaason for needing sand(recommended by univeristy of Arizona Ag dept) is so the soil doesnt recompact as the organic matter decomposes.  Since mulching doesnt yield much organic matter penetration to desert soil, something is needed to keep the soil from recompacting and sand helps there at 1/3 of the planting hole.   Seems like everyone has a different answer here, and that is partly because of environment of gardens and highly variable "clay soil" types.  "Clay" is very variable properties because of the variable macrostructural arrangement of silicates and metal oxides that provide the electrostatic binding forces.  In the phillipines I expect the soil will mulch very nicely due to the high humidity, so I would do that as a first action.  If the clay is high pH, sulfur additions will help to lower it faster than mulching but it will still take a couple years.  The mulching has worked well in my FL garden, but didn't work in my arizona garden.  The roots in the top of the soil dried out and died back when I mulched, and the granite rock prevented that.  In order for the soil drainage to change permanently you have to break it up chemically, and how to best do that will depend on where you live and what your soil/weather is like.  And yes I have read about soil differential from planting hole to surrounding soil causing roots to grow back in.  That is why you need to chemically change the soil with gypsum(sodic clay), sulfur(calcerous clay) and humic acid which stimulates root growth and chelates excess alkalais in the soil and allows those alkalais to rinse away with watering.  I did all these things and found plenty of roots 10' outside the ammended area so no I didnt have those problems.   But I can say that some neighbors had some seriously stunted trees in that soil, probably did have roots turning back, like they were grown in a big pot.

[Tyrone]

16 hours ago, sonoranfans said:

In order for mulch to work in breaking up clay soil there has to be some humidity to keep it damp so the microbes can work on it.  When I lived in arizona, I found that to be difficult, the top mulch dried out and blew away mostly and if I kept watering the deeper soil wouldnt dry cycle and I'd get root rot.  I always lanted 1/3's sand organic clay for an oversize plan ting hole(3x rootball). work organic matter into the soil.  The poor function of mulch in the desert is one of the reasons they use granite rock as a surface dressing out west, it keeps the soil under it moist, a lot better than mulch, and reduces the moisture gradient in depth so you can dry cycle more uniformly.  Here in florida, mulching works very well as the sandy soil is easy for the mulch to work its way into and it supplies critical cation exchnge capacity which is ~zero in sand.  Clay also works well here and I do have some at depth 2-3' in some places.  With clay you get nice cation exchange but you also get a variety of macrostructural clay some of which can be impenetrable to water and roots.  They use clays to line storage ponds and prevent them from leaking into the water table but most gardeners dont have that kind of clay.  I had variable clay compaction in my yard in Az to start, so I researched how to break it up.  Gypsum works well for low calcium soils, but calcerous soils are better approached with elemental sulfur which breaks down slowly(microbiological) to sulfuric acid and subsequently forms gypsum(CaSO4) by reacting with the excess calcium in calcerous soil.  Gymsum is calcium sulfate(CaSO4) so it doesnt break down high calcium clay, but elemental sulfur biodegrades and reacts with Ca in the clay to form gypsum(CaSO4).  From what I have read, you need to till in the top 3-4" and I did this with good drainage improvements after a couple years(2-3) and two applications.  Adding in humic acid also helps remove some of the Na, Ca in alkaline soils once the soil can drain.  The reaason for needing sand(recommended by univeristy of Arizona Ag dept) is so the soil doesnt recompact as the organic matter decomposes.  Since mulching doesnt yield much organic matter penetration to desert soil, something is needed to keep the soil from recompacting and sand helps there at 1/3 of the planting hole.   Seems like everyone has a different answer here, and that is partly because of environment of gardens and highly variable "clay soil" types.  "Clay" is very variable properties because of the variable macrostructural arrangement of silicates and metal oxides that provide the electrostatic binding forces.  In the phillipines I expect the soil will mulch very nicely due to the high humidity, so I would do that as a first action.  If the clay is high pH, sulfur additions will help to lower it faster than mulching but it will still take a couple years.  The mulching has worked well in my FL garden, but didn't work in my arizona garden.  The roots in the top of the soil dried out and died back when I mulched, and the granite rock prevented that.  In order for the soil drainage to change permanently you have to break it up chemically, and how to best do that will depend on where you live and what your soil/weather is like.  And yes I have read about soil differential from planting hole to surrounding soil causing roots to grow back in.  That is why you need to chemically change the soil with gypsum(sodic clay), sulfur(calcerous clay) and humic acid which stimulates root growth and chelates excess alkalais in the soil and allows those alkalais to rinse away with watering.  I did all these things and found plenty of roots 10' outside the ammended area so no I didnt have those problems.   But I can say that some neighbors had some seriously stunted trees in that soil, probably did have roots turning back, like they were grown in a big pot.

I think what you have highlighted is that soil is a pretty complex subject and there are clays and then there are clays that are different. Soil chemistry is a complex subject beyond the average gardener who just wants to grow stuff in their substandard soil. I think what everyone would agree with is that it's impossible to add too much organics to a soil, whether its by deep ripping to one metre or mulching and hoping the organisms take it down deep. At the moment I dig big deep holes much much bigger than the plant and just pack the holes with rich organics in the hope that once the plant has got big and healthy from the goodies in the hole, it can basically split any obstruction apart with its roots and get what it wants. I'm also just piling on methodically lots and lots of organic material on the surface and trying to keep it moist year round. The hope is in the end I will have around 2ft minimum of high quality organic soil sitting on top of the poorer stuff and by then I will have a rainforest full of intermingled roots all looking after one another and the plants can then pretty much ignore the lowest poorest sections of the profile, just like a real rainforest.

[Kim]

8 hours ago, Tyrone said:

I think what you have highlighted is that soil is a pretty complex subject and there are clays and then there are clays that are different. Soil chemistry is a complex subject beyond the average gardener who just wants to grow stuff in their substandard soil.

This.

We don't all have the same soil, or even the same clay. The way one manages the soil for the garden will differ dramatically according to existing soil type and climate. I would never add sand to soil in either Southern California or Hawaii. Both my gardens in these places have clay, but otherwise are radically different. There are better additives, depending on what one is growing -- even cacti and succulents don't especially thrive in sand. In California, organic matter is the best for improving the hard clay soil. Hawaii, well, I have mostly broken lava and solid lava, but if the pigs come they somehow find the stinky clay-like mud and bring it to the surface, so I know it's in there, but doesn't need any amendments other than more soil when planting. Fertilizer becomes the more important additive due to the frequent heavy rains and perfect drainage.

[Jerry@TreeZoo]

Kim,

 

My guess is that the pigs are adding their own unique amendments to the soil profile.

[PhilippineExpat]

A quick little update: my foxtails have already been growing a little since I planted them. It's like there was never any transplant shock. Let's see how they do in the long term, though. 

[Cluster]

I wonder if it is pointless to try out a coconut in clay soil, or is there anything you can do to make it work while planting?

[PhilippineExpat]

21 minutes ago, Cluster said:

I wonder if it is pointless to try out a coconut in clay soil, or is there anything you can do to make it work while planting?

I tried planting a golden dwarf coconut in my garden and it did not go well. I ended up digging it up and found it had a termite infestation. I believe termites like moist soil, so I wonder if the clay in my soil contributed to the infestation or if it had nothing to do with it. 

Edited March 12, 2020 by PhilippineExpat