I'm looking at two products for next year to put in my outdoor pots:

http://www.gardeners.com/sell.asp?Pr...&RecGroupNum=5

-- For large pots, and

http://www.gardeners.com/sell.asp?Pr...&RecGroupNum=6

-- For the smaller ones.

I have a pretty big container garden, several dozen containers. I
don't have a problem watering every day, my main concern is keeping
the moisture level of the soil balanced so it isn't over watered and
it doesn't go dry.

My concerns about these a

1) Flooding when it rains. I think this might be solved by putting
about an inch of volcanic pebbles on the bottoms of the pots, then
setting the reservoir on top of that.

More importantly,

2) Buildup and concentration of fertilizer and minerals in the soil. I
like to use a liquid fertilizer, and I'm concerned that over the
months of the summer the fertilizer might become too concentrated in
the soil. Top watering and draining through the bottom washes out
buildups and impurities, so it seems that bottom watering through
what's essentially a bucket of water under the soil takes away this
element.

3) Seeds. I plant most of my seeds directly in the containers. For
some of my larger pots, will the water make it to the surface to keep
the seeds moist as they germinate?

4) Disease. Won't a bunch of water under the soil in a bucket
accumulate fungus, algae, and bacteria over the summer months?

For anyone who has used anything like these outdoors (I am in zone 5)
I'd appreciate hearing your experiences.