The forecast says it’ll be down near freezing Saturday and Sunday evening. Nights that are clear, windless and the temperature is below 45 at bedtime are the nights we are most likely to get a frost.
Bring your houseplants back in for the weekend.
To protect tomatoes and other delicate plants:
Gather some old plastic milk jugs, the bigger the better. Any large uninsulated container will do.
Fill them with hot water in the evening. Then place them out near your plants. If it is sunny during the day you can just leave them out and the sun will warm them before evening. If it is cloudy Saturday, you’ll have to heat up the water again Sunday evening.
Cover the plants and hot water jugs with plastic. The jugs can help hold up the plastic and weight down the ends of the plastic.
The preferred method of protecting plants down here in Houston on cold nights is to cover the plant gently with a sheet or old towel. Then cover the sheet or towel with plastic. Remember to remove the coverings in the morning when the day warms up. Water before and after freezes. If you just use plastic be sure it does not actually touch the leaves. You will get frost damage where the plastic touches the plant.