watering advise needed...please help
I'm having real difficulty in determining the proper amount of water to use on my plants; this is my first venture with containers. I'm sure that some would say just use your common sense but so much of that is developed from past experiences, don't you think? And those experiences were with packaged potting soil which got sloppy wet if you weren't careful. With Al's gritty mix and it's emphasis on aeration and drainage, I know the plants are going to thrive if they're properly fed and watered. For me the watering is a whole new ball game.
My gritty mix is equal amounts of fir bark, Turface and grit, all screened to be 1/8" - 1/4". I rinsed the mix and soaked it thoroughly overnight. In the days since planting, I've waited until the skewer came up with practically no dampness before watering again. I really doused the plants until water was pouring from the drainage ports. Easy, huh?
But while rereading (which I find myself doing a lot) many of Al's posts on water retention, trees in containers, etc., as well as the resulting threads, I read about a good method to use for watering. It goes something like this: Water slowly until water begins to seep from the holes. Wait 15 or so minutes. Then resume slow watering until the draining water is at least 15-20% of the total applied. (If I've read this wrong, please correct me...please!) So I gave it a shot. I tried it on 7, 5 and 3 gallon containers. I followed the steps as listed above, and came out with the same results in every case. After the first watering, one-third of the water drained away. After 15 minutes, I resumed watering very slowly; a higher percentage drained away! In one instance, 3 oz. out of a half-cup (4 oz.) drained. Other times it was 2 oz. out of 4 oz., 6 oz. out of 8 oz. (also, 5 oz. out of 8 oz.). I apologize for being so long winded. The point I'm concerned about is that, right from the beginning, much, much more than 15-20% of the water drained away ... and the percentages only increased as I watered more. Can I be watering too much? In this experiment, when I watered the tree in the 7 gallon container, I initially poured in three cups of water; one third drained away! Was three cups too much?
Please tell me if I'm misreading or misinterpreting the 15-20% advice. Better yet, will someone give me an estimate of how much water should be used for 7, 5 and 3 gallon pots? I know it must sound as if I want my hand to be held and, maybe to a degree, I am. ;-) I'm just asking for your advice where I went wrong so I can correct it.