Cold protection - winter action for your plant collection

A note from our customer: Last winter was very cold here in Arizona, lower 30's. I used white synthetic sheets (called frost cloth, it is very light and yet effective) to cover my fruit trees, and kept simple light garlands on for the whole night. Sending you couple photos so you can share with others. It worked pretty well for my plants and no cold damage!

With winter approaching, it is time to take some actions to protect your rare plants from cold stress and damage.
If you live in a mild climate, you still need to get ready for the cold nights. When expecting a cold night, individual plants and trees can be wrapped with sheets, or blankets, to protect them from the wind chill. Christmas lights is a good idea for an additional warm up.

For large collections of tropical plants, temporary winter greenhouse doesn't have to be expensive. An easy-assembly mobile carport from a hardware store covered with a plastic or fabric will cost you $100-200. It can fit a hundred plants or more!

If you live in area with a hard freeze, Southern exposure windowsill will work for most of the compact tropicals providing proper care. Larger collections may also move into your garage for a few cold nights, or for longer periods if the garage has a bright light source.

Factors affecting tropical plant winter survival:

1. Duration of cold period. Tropical plants can't stand long periods of cold. A few days of even upper 30's may kill a tropical plant. A few hours of frost may cause leaf drop but the plant will recover.
2. Minimum temperature - of course, the warmer the better. But see 1) - if cold is not for too long, it may be OK.
3. Wind-chill can be more dangerous than low temperatures.
4. Exposure. Southern slopes get warm during daytime and stay warm longer.
5. Protection with a house, fence, larger trees - where a "pocket" of warm air forms and stays - is beneficial.
6. Humidity. A lake or a river nearby (especially ocean) will mild the micro-climate.
7. Individual species hardiness. Don't try to grow Orchid Tree outdoors in New York.
8. Plant maturity and health. A well-established plant with developed root system has more chances to survive cold. If a plant had a good change to develop during warm season (bright light, enough water, fertilizer), it will be more cold hardy. Healthy plant can withstand lower temperature, so proper nutrition is important, including micro-element applications. Large specimens, even ultra-tropical, may survive cooler winter than they normally do in their natural habitat. The Nature provided plants with better hardiness level than it is normally used. To boost plant immune system and improve cold tolerance even more, use SUNSHINE plant boosters. SUNSHINE-T - thermo-protection booster, is specially formulated for winter protection of tropical plants. To improve cold hardiness, spray 1-2 days prior to cold with 5 ml/1 gal solution and continue applications with 2.5 ml/1 gal solution every 10-15 days throughout winter period.
9. Gradual temperature decrease is less dangerous than a sudden drop since it gives a plant a chance to adjust. One sudden freeze in December with prior warm fall may create more damage than a gradual temperature adjustment. If it starts to get cold early in the Fall, plants slow down their metabolism, and the new tender growth won't get hurt later in winter, since the plants are "expecting" the cold.
10. Do not fertilize plants during cool months. Not only because they don't need much food beyond growing season, but also because fertilizer (especially Nitrogen) encourages rapid tender growth that will be damaged by cold and this will stress the whole plant.

Stay warm!

About Cold Protection...

Q: I have a question, if I'm in Okeechobee Florida zone 9b are there any plants that you sell that would have to be protected at all? I have a lot that I've purchased from you and don't want to lose any of them winter.

A: Sometimes it is hard to guarantee if certain plants are hardy enough in certain area. From our experience, tropical plant performance in non-tropical areas depend on many factors; a lot of times plants appear to be hardier than they are believed to be. Other times, an obviously hardy plant doesn't survive winter. So there always will be a chance of risk involved, while nice surprises are not an exception. We have been testing many tropical species throughout many years of our nursery experience. Wind protection in many cases is more important than temperature. Enclosed sections of your garden provide better chances to survive cold snaps. Generally speaking, here is the list of some plants (not complete list, just examples) that in our experience have been surviving light freezes without significant damage.

Q: I live in San Jose,CA. Got Mango Alphonso 2 yrs back and protected it for a year in a pot during winter. Last spring I planted it and during winter I put a freeze cloth to protect it but it died. How can I make sure it wont die if I buy this time plz?

A: Mango trees are tolerant only to light frost, once established. If it gets below freezing in your area for more than a few hours, and especially if you have numerous nights with frost throughout winter, we recommend to keep mango tree in a pot. This way it can be moved to protected area during cold night. The more established the tree, the more chances to survive colder temperatures.
We also use plant booster Sunshine to increase plants cold tolerance
Cold protection is a lengthy subject. You may also use propane heaters during cold nights.
Here is some more information on cold protection.
Also, we recommend to check out our magazine Tropical Treasures (about pushing the limits of tropical gardening) for a detailed article on cold protection.
These are specific articles on Zone-Pushing in different issue #s regarding dealing with cold. See downloadable issues:
(#1) Growing Tropicals in Nontropical Climate, Three Freezing Nights in Southwest Florida
(#2) Temperature drops - an alert or a rehearsal?
(#5) Dealing with cold snaps, Cold hardy beauties
(#7) When winter is around the corner, Growing exotic Cordyline in colder climate
(#8) When the weather outside is frightful
(#9) Winter champions
(#11) Ready-for-winter checklist for in-ground plants
(#13) Winter checklist
(#18) Dealing with cold damaged plants
You may also order hard copies.

If temperatures drop below freezing in your area, remember to add Heat Pack to your order!

Seven rules of cold protection for tropicals

Q: I was always wondering how you guys manage to grow true tropical trees in Florida? I live in Puerto Rico and we have Breadfruit trees growing here in a wild... but my sister lives not far away from you, in Orlando, which is much colder, and I wonder if I can get her a Breadfruit tree for Christmas?

A: Your sister can grow a Breadfruit tree in Orlando either in a pot (and bring it indoors during cold periods) or in the ground inside a structure (an elclosed conservatory with heating system). See our customer's Greenhouse in Virginia. Cold protection of tropical plants is a lengthy subject and we have many interesting publications about it in our managine Tropical Treasures and on the website. In a nutshell, when growing tropicals outside of tropical climate, you need to follow these 7 rules:
1. Cut watering to a minimum. Cold+wet kills tropical roots.
2. Water thirsty plants before a cold night. Jucy leaves have fewer chances to be cold-zapped.
3. Wind protection is more important than a temperature drop. Plant tropicals close to a house or surrounded by other trees.
4. Duration of a cold period is more critical than the cold itself. If expecting long cold hours, bring up all available protection resources. Christmas lights or propane heaters - as long as there is a heat source, everything helps!
5. Remove plastic covers during the daytime so plants don't get "cooked" in the sun. Fabric covers are better than plastic.
6. Grow ultra-tropicals in containers and bring them inside the garage or even indoors during the cold.
7. Use SUNSHINE plant boosters and feed your plants well during Summer to improve cold hardiness.

Related topics:
About Cold Protection
Cold protection - winter action for your plant collection
Improving cold hardiness before winter: fertilizer and micro-elements
Cold hardy tropical fruit trees