I saw something on Joy in the Garden (a Salt Lake TV show) that says you can plant tomato seedlings in a Wall O Waters now, and have very early tomatos. She said that when water freezes it gives off heat, and this is what
protects the little plants.
Has anyone tried this? It isn’t REAL cold at night, but it is getting into the low 20s. I have three Wall O Waters, and will plant some seeds to try to get something going if it seems reasonable.
A. Do not count on Wall-O-Waters, or anything else out in the garden, to sprout your vegetable seeds and get them going! Nature has dictated that seeds need consistent warm temperatures to sprout, and so you need a greenhouse, light box, or light table, etc. to do that effectively and get healthy vigorous plants.
So far as using Wall-O-Waters for protecting tomatoes, etc. from freezing, I would not count on them to help you below about 30 degrees fahrenheit. You will be much better served to keep your plants in a warm environment with plenty of direct sunlight until the danger of hard frosts is past – and why take them out even then if you have room for them in the protected environment? Your plants will be dormant at temperatures below 50+ degrees, and will likely be slowed more than helped by taking them to the garden too early.
Some folks think having them in the soil early acclimates them and makes them more sturdy. Dr. Mittleider says you need only 2-3 days to “harden-off” your plants outside before planting them, and they will do just great, assuming the weather in the garden is warm enough for them to grow.
If you will grow your plants under ideal conditions, you can gain a 4-6 week advantage over planting in the garden early, and thus have a much longer harvest season, with ripe tomatoes by the first of July in Utah and similar climates.