And suddenly, while wondering where to store them until next year, I saw The Light !

Take six or seven 2 liter bottles. Group them around one in the center so you have a circle of bottles.

Duct tape the group together at half-way up.

Now pull out the center bottle so you have a kind of 'donut'.

Put in the garden over a new tomato transplant. Fill with water from your hose.

Instant Wall-O-Water.

Cost, 10 cents deposit each in Michigan, plus duct tape.

Plants will get some light from through the 2 liter bottles and eventually grow above them.

The heat of the sun will warm the water in the bottles.

Six bottles times two liters is 12 liters.

That's three gallons, roughly.

One BTU is the heat stored in one gallon of water by one degree Farenheit.

If you can store twenty degrees of warmth during the day, that gets you 60 BTU's of heat stored for the cool nights.

Throwing a cap over this setup would conserve that warmth to deter fr*st.

And it's not unreasonable that you could store more heat in the water than that.

Paint the bottles on the North side of the plant black to store more heat. Add a pinch of salt to the water to push the heat storage a bit.

You might get up to 120 BTUs stored in the bottles, ideally.

Enough to last through a 38 degree night. Maybe.

Advantages of bottles include that they can be tossed when the need has passed without any significant cost factor.

Chey

I've seen these doodads where you get a 1 pint water bottle on a spike, and the water bottle contains watering crystals.

I have a bag full of those crystals. I've been thinking that putting them in a 2 liter bottle, adding water, waiting for the crystals to swell up, and then poking some holes would work.

As the crystals heat up in the sun, they start to sweat out their hoarded water and it drips on the plants.

Re-hydrate by dunking the 2 liter in a bucket of water.

Chey

Not expensive.

As for using just water, I'd think it would leak out in less than an hour.

The bubble wrap was most important in protecting the plants from wind and pests. We get afternoon winds every day, plus some rainstorm winds intermittently. Usually birds eat anything they can find in early spring, including young tomato plants, but the bubble wrap was a deterrent. One of the other gardeners in my community garden keeps the WOW all summer as a rat and squirrel barrier. (She keeps the tops turned down because she has noticed mosquito larvae in the open tubes.)

The stores sell some type of ceramic cap with a bottle but those are expensive, about $10 each. Anyone have any other ideas?

If you don't have tomato cages you probably will need to make some. I only let them on long enough to get the plants thru the first month of planting; then use string line draped from the greenhouse perlins to support plants. But it will make a difference. I plan to expand on this method this year since all fossil fuel heat sources are expensive.

"I always thought filling 1000+ soda bottles for 150 tomato plants..."

You must be raising tomatoes to sell. A dozen or two tomato plants keep our family well supplied. I'm interested in your garbage bag wall-of-water. I think I may experiment with that. I have several tomato cages that I made from concrete re-mesh wire. Most of them are 4½ feet tall, so I may have to use a few of my half-height cages for the experiment.

Incidentally, I use 2-liter soft drink bottles to make 1-liter pots to start large seedlings in.

MM

I read a suggestion to cut the bottom off a bottle, invert into plant with a small hole in the bottom, then put a plastic ziploc bag inside with water in it. Most plastic bags leak slowly over time, so that ends up as a drip system. I'd probably only use that as a system to not water as often, rather than a vacation situation.

Alice

I have experimented with this bottle watering method.
1- it is difficult to control the flow.
2- If you tighten the cap, the flow will slow down and may
last for 24 hours (with a gallon milk bottle)
3- The bottle will start to collaps, when lid is fully tightened. This is due to simple phisics of pressure inside and outside the bottle. If you dont fully tighten it, the water wont last very long.
4- with the wick system, I would think that the fabric will be clogged with the salts and sediments in the water and stop functioning. But to prevent evaporation, you can = use a 5-gal bucket
= fit a flexible plastc tube to it , (to come out, bent downward all the way to the ground.
Stick your wickin material inside thid tube, going all the way to the bottom of the bucket, but few inches down into the hose (bent downward).
The advantage: water will not evaporate, because it will drip directly on the soil throug the hose. Also the wick will stay wet, even if you run out of water.
=I am not aware of the effectiveness of the wick system(whick is supposed to work on capilary principle).
and as I said, even if it worked for a while, soon it will be clogged up.
The idea sounds great but will it work? I may experiment.

A. Cut the tops off bottles at highest widest point.

B. Place a few small rocks on the bottom of the bag just enough to weight the bag down then add soil,fertilizer plant or seeds to zip lock bag, zip bag partially closed.

C. Fill bottle with water partial way up.

(Other container ideas lrg styrofoam or plastic cups).
As the plant starts to grow bag can be unzipped more
D. When plant is ready to be transplanted to permanent location just scoop out of bag with soil and place in the ground undisturbed.
I don't know anything about science stuff but I think this may work?? I'm sure going to try it.