Can't figure out why my DIY soil mix has poor drainage

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xDannyS_

Member
I'm hoping someone can help me figure out what's wrong with my soil mix. The drainage is perfect during first watering, but after it dried and is watered for a second time it puddles and drains super slow. It's sticky and feels like it has clay in it, even though I'm 99% sure it doesn't. I don't directly add it and it's not listed on any of the products I use. I can't seem to figure out what's wrong. Initially, I thought it was my compost, but that doesn't seem to be the case anymore.

My mix:
Coco coir 33% (I've also tried coco & peat and just peat)
Compost 15%
Worm Castings 18%
Lava Rock 20%
Pumice 14%

Amendments per 7.5 gal:
Neem meal 1/2 cup
Bone meal 1/5 cup
Langbeinite 1/4 cup
Kelp meal 1 cup
Alfalfa meal 1/4 cup
Lime 4/5 cup
Dolomite 1/5 cup
Basalt 0.01-2mm 1 cup
Diabas rock dust 1 cup
Gypsum 1 cup
 
OldMedUser

OldMedUser

Well-Known Member
For my larger pots I till the surface with a big old serving fork I got at a thrift store but if really dry on top it still takes a bit to start soaking in. I'll hit the roughed up surface with the spray bottle first then it goes in easy but I still only add a bit at a time to it doesn't just pour thru. A few drops of blue Dawn dish soap will work as a good surfactant to help the water spread nicely and only has to be used once in a while or you can buy a commercial product like Wet Betty by AN. A lot of guys use aloe but I don't know which product they use.

I'm using ProMix HP with some added organics like 3 types of manure and some of the things you list.

Wondering why you use so much lime compared to dolomite? Dolomite alone is great and lime reacts very fast so your pH is going to be high. Lime can just be mixed in water then added later if pH drops.

Personally I think you have too much stuff in that amount of medium but growing will tell the truth. :)

Good luck!

:peace:
 
X

xDannyS_

Member
GrodanLightfoot said:
How much $ did you spend on that 18% worm muck.
Click to expand...
25 EUR for 60 liter. Using it for my other plants as well.

OldMedUser said:
Wondering why you use so much lime compared to dolomite? Dolomite alone is great and lime reacts very fast so your pH is going to be high. Lime can just be mixed in water then added later if pH drops.

Personally I think you have too much stuff in that amount of medium but growing will tell the truth. :)

:peace:
Click to expand...
I already have a lot of magnesium in my other things so I was worrying that the one from the dolomtie will be too much. I was told a total of 2 - 2.5 cups of amendments per 7.5 gallon, which is what I have.

Budzbuddha said:
Where did you get this mix recipe from ?
Click to expand...
It was mainly from Rasta Roy but modified since I can't get things like crab meal, fish meal, and a few other things here and I also already had quite a lot of amendments from other projects.

I ended up figuring out that it's related to my amendments. The tests I've done since posting this made me come to this conclusion. All tests had the same mix, but one half was with amendments added the other without. The ones with the amendments all ended up having the same problem again while the ones without are still draining perfectly.
 
PopAndSonGrows

PopAndSonGrows

Well-Known Member
I think your amendments are making the surface of your medium "hydrophobic". Just a small tilling of the surface, like just move it around with your fingers a lil bit, should work.
 
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Gumdrawp

Well-Known Member
Do you use a mulch layer? Unless you're using wetting agents without something stoping surface evaporation thats going to happen when your surface dries out. You just need to break the hydrophobic surface layer basically. You can either scratch the surface, water in a couple smaller increments, use a mulch layer and try to keep it moist at all times, or use cover crop so the root systems help the water penetrate the top layer of soil.
 
J

JHake

Well-Known Member
Compost texture is my first bet.

You can go with that 33-34% of EWC/compost, but make sure both are great in texture.
And if you want to go up to 33% i would only use EWC or mostly EWC.

I even use only 20% EWC because in the long term, coco/peat become more like compost in texture.
 
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