Hi, Wyndell. You can use the bark based mix in self watering as well as conventional containers, as long as the soil's capillarity (ability to wick) is sufficient to keep up with the plant's water use & evaporation. This is primarily a function of soil particle size, and secondarily a function of what ingredients the soil is made from.

How often you need to water depends on a combination of several things, but the main factors are the soil's ability to hold water and the mass of the plant material in comparison to the soil mass. Decreasing component particulate size will increase water retention, so perhaps using a finer bark product would help. You could also try using some rockwool in place of some of the perlite component.

You can find perlite at most large nurseries or greenhouse operations in 4 cu ft bags. It's quite inexpensive in that quantity/size. I think I paid $14 for the last bag.

The fertilizer in the strip gets to the plant because there is a tendency for soluble concentrates to move from a hypertonic state (a high concentration of solutes) to an isotonic (balanced state). As long as water molecules have enough space between them to "fit in" additional molecules of fertilizer, the fertilizer will dissolve and disperse through the water in the soil mass.

Generally, the bloom booster fertilizers are much ado about nothing. P shows up in plant tissues (including flower and fruit tissues) at only about 13-19 parts for every 100 parts of N. This means that plants need about 6 times more N than P. If you use a popular blend of bloom boosting fertilizer like 10-52-10, you're supplying about 30 times more P than the plant will ever use. It makes no sense and it's difficult to make a case for the use of a hi-P fertilizer. High P levels are also known to have an antagonistic effect on both Fe and Mn, making both increasingly unavailable for uptake as P levels increase.

Al

Thank you Al

I checked on the nurseries around here and the only one I found was $35 for 4 cu ft. I'm waiting to see if any of the others will special order it for me. I have seen something called oildri at sams which is listed as a potting soil aid as well as soaking up oil. I would rather use what you recommended though. We are hoping to move this summer so most of my plants will be in containers so I can take them with me.

As for the fertilizer, does it move even though it isn't supposed to get wet? I guess thats what confused me.

I'm not sure what rockwool is but I'll do some more research and find out, lol.

thank you again for the quick reply

The $35 seems mighty stiff to me, Wyndell. I would look around, too. Oil-dri can be a very good addition to soils & is a good substitute for Turface, if it's fired at high enough temperatures. Soak it over night in water & then squeeze it hard. If it breaks up or turns to mud, it's not suitable. I usually don't use Turface in my short term soils (like for the veggies & annual pretties). Because of the higher price, I usually opt for perlite in the short soils (one year) and a combination of Turface and crushed granite in houseplant soils or soils for plantings that will go two or more growth cycles between repotting/root-pruning.

Yes, the fertilizer moves/disperses when the absorbed water wets the soil particles it is resting on (that whole equilibrium/isotonicity thing)... Experiment: Put a clean sponge in a shallow pan of water, then place a sugar cube on top of the wet sponge. Before long, the sugar will all be gone - completely dissolved. Taste the water in the pan - it will be sweet and the sugar dispersed evenly throughout the water in the sponge and the water in the pan.

Rockwool is made by melting a combination of rock and sand and then spinning the mixture to make fibers which are formed into different shapes and sizes, and then, often ground. The process is very similar to making cotton candy. Rockwool has some pros and cons though, so before you decide to use it, please do a little research. ;o)

Al