What can I make to keep my plants warm in my sunroom that has no heat?

some of the grow bulbs generate a bit of heat, and there are heat mats for seedlings. i dont know how many plant you have. i have used pvc and connecters make a large cube and covered it with 4 mil plastic sheeting. adding the old fashioned heat lamps.

Hi, Nancy. Covering the windows to keep out some of the cold would help. Try the 3M window system that you shrink and it will keep out some of the cold that comes through the windows as well as the cold air that comes around them. You could use a grow light, to make sure they get enough light and that may add a little heat. If you do use grow lights, you would not have to have sunlight come in from outside and you could possibly use insulated drapes over the windows to keep the cold out and the heat in. You will need to keep the hibiscus at a minimum of fifty degrees, but higher would be better for the plants.

look into solar heating. If you have a sun room and it gets enough sunlight this might be your answer. sometimes just putting up some black plastic strips might draw enough heat. Mother nature magazine has lots of ideas for this. A friend took a bunch of cans and cut up pvc all the same size, painted them black put them between Plexiglas and this drew in a lot of heat. the one side of the tubes can not touch the glass allowing it to vent down or up. here is a web site for solar https://www.alibaba.com/showroom/solar-heater-greenhouse.html?src=sem_bing&cmpgn=304035522&adgrp=1300722279279237&tgt=dat-81295155619344:loc-190&KwdID=81295155619344&mtchtyp=b&bdmtchtyp=bb&ntwrk=o&device=c&creative=81295153873305&p1=default&p2=default&p3=default&Query=solar%20greenhouse%20heater

Depending on how much sun light you get, you may be able to help them with a little passive solar heat. Put some large clay tiles under the plants. Look for some that are dark and have a high iron content, they will absorb the most heat. BUT in an unheated room the warmth will dissipate without much going to your plants. I too have heard that you need a minimum of 55 degrees. If you opt to cover the windows why not try bubble wrap? Just spitz the glass with water and press the bubble wrap in place, you will still get a good bit of light thru. To help with the night time temperture drops look into an electric heat mat to go under the tiles, but make sure the plants are in plastic, leakproof saucers before doing this.

GET SOLAR HEATER YOU CAN ADJUST THE RIGHT AMOUNT OF HEAT YOU WANT

If you look for the electric heaters that have a fake fireplace front, you will find them very efficient. The one in our bedroom has the lowest setting as 62 degrees F. Don’t keep the plants next to the outside walls. You can use full size mirrors ($12 at Dollar General and Walmart) and other sizes, as well, to reflect the sunlight onto your plants. On the night when the temp is supposed to get down below freezing, cover the plants with thick plastic, a supported tarp or blanket, and towels under each plant so they are not sitting on cold surfaces. If you can find room in the house for even some of the plants, move them inside. It should be between 50-70 degrees in the rooms with plants. As long as they don’t get too warm, watering once a month should be enough. Best wishes 😇