Hi Sally,
I don't actually have anything to contribute about the wall o water towers, but as far as extending the season...you could ask Marie (Selkie b) about her phenomenal sucesses with earth boxes....

I just ordered some about a week ago. Thought it might be worth a try. Sounds like it would work well.

They do indeed work. They have used them at the arboretum veggie show gardens from time to time. Can't say how much early you can plant, but even if you planted at the normal time they could be put to good use by keeping plants cozy at night.

The water towers work to a point. Most vegetables in the garden will catch up.
What really WORKS is red mulch. I used it for the first time last year and I had an over 25% yield increase and groth factor. It was amazing
It looks weird but people around here expect weird in my garden

Thanks everyone. And thanks for the comments on the red mulch. I've been wondering about that.
Sally

Are you able to plant any earlier by putting the red mulch down, or does it just make the plants grow better? Do you put anything under the mulch?

BTW, just got my wall o' waters in the mail yesterday. Can't wait to try them out!

I made my own WOW using 20 ounce pop bottles. Used a glass quart jar as a temporary center, then tied the bottles together and used heavy grade construction adhesive to secure them. Removed jar from center.

They worked great and I could plant about 6 weeks earlier than usual. When it got real cold, I cut off the bottom of a gallon milk jug and placed the top over the homemade WOW.

I have been using WOW for 15 years. They are easy to set up if you use a 5 gal. plastic bucket over your plant to hold the WOW while filling. Our spring temps. can be 65o F days and drop 50o at night to 15o. They protect the plants, warm the ground and retain moisture. We can gain up to a month growing time. WOW develop leaks and need attention as they age. The 6 pack tube repair kits are just tube inserts for the leaky tubes and are easy to insert.

The first time I used one, something chewed holes in three of the tubes, so the water ran out of those and it collapsed on the plant. Our garden is very sandy, so I suppose some critter was thirsty. Northwoodswis

I used them this year for the first time. I usually try to grow one variety of extra early tomatoes, so this year I used the WOW with my container "Legend" tomatoes. We were able to get some tomatoes just after 4th of July. I also used one of those flimsy tomato cages for support. A couple of the tubes did develop leaks. Overall, I am happy with my results and will use them again.