Soil basics - Don't forget the perlite!

Hi all this is I think the most important ones on this forum. It seems though to be one of the least visited. I wish I had put more thought in my soil before I started this, my first grow.

Even coming here I expected to see at least a few that talked about what they did about the soil. I am wondering if people learned the way I seem to be at this weed farming. Trial by error.

Well the one thing I can tell you beginners before you put your seed in the soil take a minute to learn what needs to be in it and why. Don’t miss the easy ones.

If you go and get a bag of organic composted soil like Fox Farm you don’t need to add too much to it. You could even cut it some with some Canna Coco. This is purified dirt and basically neutral just a medium to help hold the roots. You can add in some seaweed for iron and sulfur to put a bit of acid in the soil as well as aerate it. But speaking of aerating this is absolutely critical. You need to put some perlite in the soil. Mix it well and you can easily use 16 quarts of perlite and your plants will thank you for it.

What I have found is that the perlite allows the water to drain away and gives the roots pockets of air to help grow. It is funny I don’t see much of that mentioned until I got to investigating it in my own failures. The one key ingredient I needed.


Thanks for sharing :+1:


I used a pot inside a pot system for my current grow where I had holes on the inner pot with a soilless media and the outer pot has 70% perlite which allows the roots to seek out oxygen on their own.


Hi @GreenCoat yeah that is kind of why fabric pots are so good for that. While the roots don’t like the light they can find their way into that fabric for the oxygen it needs. I saw your comment on another journal yesterday and liked it. I would have replied but I had already posted this in the soil area so thank you for the post on there.

I so wish I knew the secret of perlite before I started this. I might already be in flower. They would have been very small because my first tent was 4 foot and I had a burple light. Yeah it was a cheap set up but because I didn’t use any perlite and in fact used vermiculite (this is really an important point). I was pounding the piss out of my root system. Lesson learned in short order of about 2 months.

I don’t mind though. I got a great lesson in growing. I am retired and this growing stuff is going to become a hobby. I have a nice piece of property and a fairly large vegetable garden. My mother-in-law has been enlarging it since we moved in 14+ years ago. Now that my wife and I are retired we will have more time growing in the garden.

I just hope that the next newbie will see my post here. This is such a critical thing that if you don’t start out with the right foundation even a weed is going to die in it. An indoor grow the nice rich soil you made with all those nutrients and additives becomes a wall of mud and packed earth. Those little itty bitty roots just don’t have a place to reach in there to get food and water and oxygen. It isn’t as important outside because mother nature helps. But if you really want a good yield outside I imagine that perlite can really be a big boost to the soil too.


@Oldsoldier1976 If you want to learn more about indoor soil mixes @garrigan62 has a great recipe. I haven’t personally tried it yet but he has had excellent results with it.


Next time :wink:


Can anyone explain the difference between perlite and vermiculite??? Thanks

Vermiculite will help keep soil loose, but will also retain moisture, perlite does not retain moisture.


@SteveC exactly. There needs to be some water retention but that is not nearly as important in our indoor grow environment. One of the things that I am learning in particular some strains Maui in particular likes a drier soil. One that drains well. I don’t plan on changing the soil I am growing in now but next time I grow I will tailor the soil much more to each of the strains. Thanks for that answer Steve.

1 Like

Would you want both? Or just the perlite? Using FFoF.

Use both but a lot more depends on the root area being able to dry out to force the roots to look harder for moisture and food. So perlite in a larger portion than vermiculite.

1 Like

I’m on my first grow. 5 gal. cloth bags, and Happy Frog @100%. Wish I had added either/or to the HF, and have learned why the hard way. I can now see either could be beneficial, you just have to change your watering habits accordingly.


In a 5 gal pot, what percentage of each do you recomend to use?

From my limited experience, I’d probably add 20% perlite. I’m able to check them too many times a day, so probably no vermiculite. If my schedule kept me away for maybe a day or more, I’d add vermiculite, but how much, I have no idea yet. I thought the HF soil seemed almost water repellent when I first planted with it, so added nothing, but as it ages, it does tend to clump.

1 Like

So should I illiminate the vermiculite?

I don’t think it’s needed if you’re able to keep an eye on the plant’s moisture needs, but if you already added it, just realize the plant won’t require watering quite as often, which isn’t a bad thing, either.


No time or access issues so I can keep up with watering so looks like the vermiculite is unnecessary. I’m in the final stages of accumulating all I need for this upcoming grow. TDS meter and nute’s are all I need at this point every thing else is taken care of (I think) Just ordered some perlite to ad to the FFoF.


I’m with Steve on this. Vermiculite would only be an insurance against under watering. I think some in an outdoor grow would be called for.

20% is a good base for the majority of the weed grows. Some might like more or less perlite (better drainage) there are a lot of variations. This is especially true growing indoors.


Got more than enough coming for 20% so what about Cal/Mag?? Should I have this on hand? Or is the FFOF goof enough?

from what I have read there is rarely an instance of over feeding calcium and magnesium. I hope others will chime in on that as well. I think that young plants could uses a bit of silica as well. It is kind of like drinking milk for plants in general. It uses the silica to build strong limbs. I have both cal/mag and a silica supplement as well. This is what I have started using.

1 Like