Hi PeterI am building a sub-irrigated raised garden planter, and everything thing I read says to fill it with a potting mix, which is light and fluffly and won’t compact. They do not recommend using topsoil and manure. My issue is it will cost me a fortune to fill it with bagged potting mix since it is 3 feet by 6 feet and will be 16 inches deep. Do you have any suggestions for making my own potting mix, or do you possibly sell it in bulk?Please reply to Thank you
I expect the reason for the potting soil requirement is that the moisture needs to get “wicked” up to the root zone. Heavier soils won’t do this as well as peat based potting soil. The options are to skip the from-the-bottom irrigation and use a blend of compost and sandy loam and commit to traditional spot watering from the top of bite the bullet and invest in “potting soil. I’ve attached a copy of our “loading zone items. Check out the Pro Mix and other compressed bales of potting soil. the 3.8 cu ft bale will fluff out to about 5 cu ft or more. This is what greenhouse growers use. You’ll be able to reuse it for years so it is an up-front cost. With the bottom irrigation, you can’t layer soils…it has to be the same soil from top to bottom.