Earthbox's
faq says
"What kind of fertilizer does the EarthBox need?
Each time you plant in the EarthBox, use 2 cups of a dry, granular fertilizer or plant food for vegetables (use 3 cups if the fertilizer is organic). The three numbers of the elements making up the fertilizer content (NPK) should be in the range of 5 to 15 (i.e.12-8-10, 10-10-10, 6-8-10) for non-organic fertilizers. "
and
"Can I use organic fertilizer?
Absolutely! Many EarthBox gardeners prefer growing their plants organically. We have recommended several brands of dry, granular organic fertilizers that can be used by placing 3 cups of organic fertilizer, in the form of a strip, in the EarthBox."
I use whatever fertilizer is on sale with the appropriate NPK (which happens to be
Ecoscraps' Rose and flower food, lower N level and was on clearance). We need to keep in mind that the NPK numbers are what is immediately available to the plant, so when they say two (or three) cups, and a cup is mostly around a pound; then we are just taking the numbers up to the conventional fert numbers.
I agree, Promix is expensive and I regret using peat (mixed my own). I have used the Just Natural but as regular in planter potting mix. With hand watering, I think the plants didn't get the aeration they needed.
If I could start again I would buy a
Coco Coir brick and get pearlite from Home Depot. No more adjusting pH with lime
