Perlite To Soil Ratio For 1.5 Cu. Ft. Bags
- Thread starter Milovan
- Start date
Nullis
Moderator
Depends what it is you're starting with and what you want to do. I frequently read people recommending 15, 20, even 30 percent perlite or more... to be added to bagged potting mix that already has perlite in it to begin with.
So what mix is it that you're starting with and whats in it?
I usually use FF Ocean Forest or Sunshine Adv. Mix #4 as a base and I personally think that both of these contain plenty of perlite as is. Instead I just add coco coir to the Ocean Forest. The reason I am weary of adding tons of perlite is that perlite is totally inert, non-nutritive and has no cation exchange capacity. If you use too much it can collect and form pockets throughout your mix where plant roots wont want to grow.
Coir fibers, earthworm castings, vermiculite, pumice, are all alternatives that will help keep soil aerated... the former have the added benefits of being sources of carbon\organic matter which microbes can live on and have or can hold onto nutrients.
So what mix is it that you're starting with and whats in it?
I usually use FF Ocean Forest or Sunshine Adv. Mix #4 as a base and I personally think that both of these contain plenty of perlite as is. Instead I just add coco coir to the Ocean Forest. The reason I am weary of adding tons of perlite is that perlite is totally inert, non-nutritive and has no cation exchange capacity. If you use too much it can collect and form pockets throughout your mix where plant roots wont want to grow.
Coir fibers, earthworm castings, vermiculite, pumice, are all alternatives that will help keep soil aerated... the former have the added benefits of being sources of carbon\organic matter which microbes can live on and have or can hold onto nutrients.
Milovan
Well-Known Member
Thank you for the interesting and very helpful response!
I use FF Ocean Forest and was thinking of adding more perlite but
I would rather go with your advise and add vermiculite as a
alternative. I believe FF has worm castings so added vermiculite should help
with aeration and drainage? What would you recommend for a
vermiculite to soil ratio and is the cost of perlite and vermiculite comparable?
Thank you very much
btw, when you say "former" do you mean coco coir?
I use FF Ocean Forest and was thinking of adding more perlite but
I would rather go with your advise and add vermiculite as a
alternative. I believe FF has worm castings so added vermiculite should help
with aeration and drainage? What would you recommend for a
vermiculite to soil ratio and is the cost of perlite and vermiculite comparable?
Thank you very much
btw, when you say "former" do you mean coco coir?
Nullis
Moderator
Coir and castings are carbon-rich organic materials. Everything else I listed also has a CEC which means they will adsorb nutrient ions to prevent them from leaching, unlike perlite.
Vermiculite is just as cheap as perlite is. You can add that in at say ten or fifteen percent. If you can get bricks of coir I would go with that, a brick expands to 1/3 cubic foot and you can mix a brick or two in with the 1.5 cu. ft of soil mix. Make sure you add in an additional tablespoon and a half dolomite lime for each gallon of mix.
Vermiculite is just as cheap as perlite is. You can add that in at say ten or fifteen percent. If you can get bricks of coir I would go with that, a brick expands to 1/3 cubic foot and you can mix a brick or two in with the 1.5 cu. ft of soil mix. Make sure you add in an additional tablespoon and a half dolomite lime for each gallon of mix.
~3 gallons or so. I would NOT add vermiculite. That mix is plenty water retentive enough as it is. IMO, vermiculite is great is seed starting mixes and that's about it.
What Nullis says is spot on BTW. What we may disagree on is mainly different growing styles, not basics.
Wet
Dwezelitsame
Well-Known Member
ff of i mix 4 to 1
