Referred to as Tomato tee pees , water teepees, garden teepees or cloches , they are basically inexpensive sheets of connected plastic tubes filled with water, They form a self-supporting wall or protective cone around young plants. They are proven effective at extending the early growing season.
They are sold in Blue Green and Red. Red Tomato teepees are particularly effective for tomato plants, as red has been proven to enhance the development of immature tomato plants. It is believed the color red sends a false signal to the plants that they are overcrowded stimulating them to gain height and foliage at an accelerated rate.
The Blue/Green varieties work better on Peppers and eggplants. Theoretically, lacking the stress of climatic extremes, the plants can focus energy into producing fruit.
There are some drawbacks to the water tee pees.
They create a hiding spot , as well as attracting slugs.They take up more space, so in a square foot gardening scenario for instance -are not advisable.
You need to prep the ground early -- up to a month before planting They are for temporary use in to get a jump on the season when the weather is still nippy. They must be removed come full summer weather or you'll fry your plants. It can be difficult to remove them alone. You need a helper.