If you can set up sprinkers to come on 1 1/2 hour before sunrise with an overspray, it will stop the frost damage.

If it is just a one night thing, I would go ahead and protect them, by covering with plastic, bed sheets, tarp, ..any thing that I can find.
Remember that drop to frost line last just an hour or two. It is not going to lass all night long.

Pick the green ones nearing full size. Set them stem end down in a single layer in a box or tray lined with several thicknesses of newspaper (cushions and soaks up liquid if any "leak") Keep them in a cooler area of your home and check on them for ripening every few days. Put a few in a warmer area if you want faster ripening. Do NOT set them in a sunny spot, they do NOT need sunlight to ripen and overheating is not good for them. Some people wrap each fruit individually but I find that makes it hard to check for ripening or rotting and is not necessary. Expect some to rot or shrivel....they will not all make it to a ripe tomato, but a lot will.

If you think there is a good possibility the frost will be followed by a few weeks of warmer weather, covering to protect from frost is worthwhile. I will often pick the fruits closest to ripening and leave the others with hopes they will grow more and can be brought in later after being protected for a night or two. Then if the temps get colder than expected, you at least have the fruits closest to being ripe and are not trying to salvage fruit from half frozen plants.

I've picked green tomatoes in early October and had ripe ones to eat with Thanksgiving salads many years. Sometimes a few have even made it to Christmas.

When speaking of covering, do you just cover the tops, and some space at the bottom is okay, or do the entire plants need to be covered? I'm in Denver too, and would like to cover, and am trying to plan how much sheeting is needed.

I cover COMPLETELY the plants. Like a hoop house.

If you leave "some space at the bottom", cold will get inside and the cover is useless.

A picture of your plants would help.

I don't have a pic right now. We have small plot at a community garden next door, so building a structure isn't feasible or worth it. We have 12 plants, in two groupings. One set is 8 plants, about 5 ft wide x 10 ft long. The other is a row of plants. Some are shorter, but the majority are 6-7 ft tall. We also have a couple of tomatillo plants.

I have two 10x12 frost blankets. Maybe a roll of plastic around the sides, with that over the top?

balloonflower wrote:

> building a structure isn't feasible or worth it.

A very simple and CHEAP structure would be good, imo.

> I have two 10x12 frost blankets.

I would replace the frost blankets with plastic sheeting.

Here are two options: 10 ft. x 50 ft. or 20 ft. x 25 ft.

There are many other sizes. Look around.

Why plastic instead? I was happy with the blankets this spring, as my foot tall seedlings were planted before our last snowstorm. They seem much easier to deal with than plastic.

And the bigger problem with a structure is storage--can't store at the garden and have a hard time with even our trellis conduit pieces. Wouldn't be cheap enough for one time use.

HOW MUCH to cover, it depend on the nature of the frost.

Plants get injury from blowing cold wind on them, rather than from cooling down. UNLESS it is extended freezing temperature for a long time. So any amount of covering that prevents air flow around/over the plant can help. Obviously, covering the entire top would be ideal.

Hoops of plastic can work, provided they are tall and wide enough. I have couple mini ones, about 45" tall. Not tall enough for any thing right now. I have made them for spring time use.

Use tarps, blankets, boxes, heavier plastic, etc. Anything you can get your hands on. Thin plastic is not enough to prevent frost damage, though it may help if put it over or under another layer of something else. Cover from top to bottom, then anchor with rocks, boards, clothespins, rope, whatever.