With a SIP (self irrigating planter) water is drawn up from the medium via capillary action. Plant roots still get oxygen with a SIP as there is an air gap of sorts. In the second drawing the plant roots will be resting in water, and lacking oxygen. That's not to say that #2 drawing won't work.

Ideally, the pot in the #2 drawing can be raised above the water line and then a cloth wick or two could be used. At that point I'd ditch the rocks and use something to raise the pot above the water line, and then the lower dish can serve as a reservoir for the wick(s).

tugagardener, The amount of vinegar you use depends on the pH of your water. I use 1-2 tbsp in a watering device that holds 2.5 gallons. You need to measure the pH of your water mixture after you put in the vinegar and I believe blueberries like 4.5-5.5 pH.

Mr. Clint...what do you think about using the #2 drawing pot in water, but letting the water get used up and the plate(I use a deeper plastic container) going dry for a while (let's say, a week). Would that allow enough oxygen to enter through the bottom drain holes to keep the roots healthy? No stones used in my version. Would it help the situation to put some vent slots in the side of the container (5 gal and 15 gal).

John

I'm not much of a trail blazer when it comes to the garden. You're going to need to trial your plan and report the results back to us. I would purchase an engineered SIP and call it a day. The startup costs of such a system are quickly offset by how much food you harvest.

I want to add that I don't have any blueberries in SIPs, and I do not acidify my blueberry irrigation water. My tap water is pH 8. Most of my BB are 6 years old and give me a lot of blueberries. Monthly feeding with Dr Earth acid lovers formula is about all that I do to keep them going strong.

Thanks for your opinions! Jbclem has a point..if nº2 gets holes on the side of the pot it might work...i have 15 so i guess i can try in 2 and see the results...