Ok, couple of things-

Media will hold too much water for a constant drip. If yer gonna go constant, skip the soil and just use the perlite. Even that's a little wet- you'd be better off with something like hydroton. But the coarse grade perlite will work.

Heavy Harvest isn't an appropriate formulation for this system- it's designed to be spread as a top-dress in a soil garden. If you mix it into yer perlite, it'll just wash out- and not even at consistant ratios. You might get away with weekly VERY LIGHT top-dressings of yer bags, but you've already said that you can't get there very often.

You might want to look at liquid ferts and a ratio mixer- depending on the flow, you might be able to use something as simple as the dosers that folks use to apply miracle gro to their lawns. A seperate res with a line slowly, drop by drop, bleeding fertilizer into yer main irrigation feed is a more likely scenario, tho.

Heavy Harvest won't work for this - solubility issues. Will clog the hell out of needle valves.

I'd be looking at plants in the ground, using your water source as, well, a water source. You'd be able to use the ferts that you've already paid for, and walking four miles round trip isn't really that bad. Be glad that you don't have to carry water.

I know, it's not as sexy, but it'll work. The system that you're describing won't.


My $.02 US (not worth much, and plummeting daily- Thank Ya, Dubya)