I need to buy 10 yards of sand for a raised bed for some avocado trees and my ph is currently 5.7. I found a couple people on facebook on the FL/AL boder that will deliver it.
Any idea what the ph is of sand roughly?
1 Like
I would think that might depend on the type of sand. Sand that’s hard rock like quartz should be near neutral because it’s basically an inert material. Sand that contains some shells or another form of calcium carbonate could be 8+. It’s hard for me to think of a sand that could be acidic but there probably are some.
7 Likes
I doubt there’s any clear answer without testing it, since it will depend on the source and chemical makeup of the sand. Could be mostly carbonate sand (higher pH) or silicate sand (should not alter pH much), and could be from surface deposits, coastal beaches, or quarried from subsurface.
I’d also maybe want to know the salt content, depending on where they sourced it.
EDIT: @fruitnut replied while I was drafting mine, but +1 to what he said!
4 Likes
So the ph should be ok if I mix it 50/50 with my 5.7 ph native soil?
I never thought about salt? How to tell the salt level? Taste it?
If you’re not in a huge rush, I’d probably accept the delivery and then send a sample to your local extension office for soil testing (usually very cheap, sometimes even free). That will tell you not only pH but lots of other useful information including salt content. Then, you can decide if you need to wash the sand to strip salt, or add anything to alter pH when you mix it into your beds.
2 Likes
I won’t worry about salt unless your soil is already salty or poorly drained. The only salty sand near FL will be from near the ocean.
Salt is easily leached out of sand. So if you don’t have salt issues now you won’t after adding the sand.
I think you could mix any sand with your soil and still have a pH below 7. The only issue might be sand made of sea shells. That’s the same as adding limestone. That might improve your pH if 6.5 is a good area for avocado.
4 Likes
They just delivered me 20 yards of what they said was “Brown Sand” for $300. The really light sand used for mortar was $800 for 20 yards so I had to pass. I found a test to see how much sand, silt and clay is in the soil Soil Texture Analysis “The Jar Test” | Home & Garden Information Center . It looks like more clay or silt might be in the new sand I just bought than my natural topsoil so I’m trying to figure out if I can just add the new sand or if I need to mix the natural top soil with it, but I need to be sure it drains water since I’m planting avocados trees? The natural ground slopes down hill, so the ground is not flat and I will have 20" raised beds.
Uploading: IMG_20230422_081732491.jpg…
That’s a lot of sand
1 Like
Usually you’re better off mixing things. And your topsoil has lots of things the new sand doesn’t. I’d mix them together.
In your hand and in the pile it looks pretty sandy. I can’t tell much from the test. It looks like water would drain right through it. I think it will improve the drainage of your soil.
1 Like
could you give us the % results of the “jar test”?
have you done that test correctly? I can only see 2 lines. the line with a 2 seems to be at a water level instead of silt or clay…
mixing where the different “layers” of soil meet is always a good idea.
A difference in texture breaks both the draining effect downwards. But also the capillary upwards.
Just from the pictures it seems extremely sandy. i would be amazed if it didn’t drain properly.
ps: just to clarify. I would just dig up the spot of the raised bed and mix some of the new soil (sand) in it. And than dump the rest on top. I would not mix all the new soil (sand)
Just mix enough so there is a gradient instead of an abrupt line between native and bough soil. basically dump a layer of 5" of new soil on top of the old. Dig trough it a bit and than dump the other 15" to get to the desired 20" height you mentioned.
1 Like
I’m going to redo the test the first two I did correctly but I really can’t see three layers the new sandpile I didn’t mark any lines I just wanted to see if there was three layers or not
I took some sand to the local nursery and they said there’s definitely clay in it which is actually good to add nutrients. He said that sand could pack down after time it would be best to mix something with it like pine bark or my leaf mulch.
I also read avocado Roots like Oxygen so maybe some pine bark or perlite around the tap Root area might not be a bad idea but I don’t think I need to add it to the whole 20-in raised bed which is going to be 6x6
it can be normal to not see a clear difference in colour between the 3 layers. That’s why you should time/mark them.
first 60 seconds is mostly sand
next 2 hours mostly silt
next 48 hours should be clay.
looking at your new soil (sand) i suspect the lines you draw after 2 and 48 hours to be very close to the line you draw after 60 seconds. Since it looks really sandy.
4 Likes