Overwintering and Indoor Propagation

bringing plants indoors

Overwintering and indoor propagation require special attention to temperature and lighting. Let’s say you went a bit overboard with your purchases of tropicals and other cold-sensitive plants last Spring and Summer. Now you wonder if you’re prepared for that first frost and freeze warning? Indeed, miles apart are our Northeast Florida Winters from our subtropical Summers. So winter homes become forested with houseplants, potted tropicals, palms, and many high-dollar specialty plants that would probably rather not be there.

The fundamentals are the same for plants to survive. Each variety has its minimum required amounts of air, light, nutrients, space, time, warmth, and water. Know your plant’s cold-hardiness and your area climate. The temperatures along the St. Johns River and the Atlantic Ocean are warmer than surrounding areas. These aren’t reported in the area weather forecast. These microclimate conditions vary widely associated with factors that limit wind and temperature exposure such as large tree canopies, dunes, and structures.

If you decide to bring in plants, thoroughly inspect the foliage and soil to avoid bringing in pests that might spread to others. Like your own health, the more time and effort you put into your plants’ health, the better off they will be. Many of the same pests you protected your plants from outdoors would love to do more of the same damage indoors. And the conditions improve indoors for some pests like spider mites. Clean the plants removing damaged foliage and leaf litter that make nice homes for pests. Reduce the plants watering schedule and position away from heat and drafts. Know your plants, which involves more than a google search, but getting to know them from hands-on experience.

Oh, and before you packed all those plants indoors, did you consider each of their light requirements? You may have perfect indoor low, and medium-light suited for your Sansevieria and Dracaenas, but not enough window space with sufficient lighting for all the other plants you want to bring in. Experience will say it’s the sort of thing you realize wasn’t totally planned out that you can improve on year after year. Yet, we want to have a thrive, not just survive, attitude with our gardening. But, there is a lot to learn. “Seedlings need more light than full-grown plants, ideally as much as 16-18 hours a day,” according to PlanetNatural.com. “We’ve found that a window sill, even a sun porch, doesn’t provide enough light to grow strong, healthy, compact starts.” Research your plant’s needs and figure out if it might be better to leave some of them outside, possibly covered with freeze cloth. Potted plants left outdoors should get extra protection as you don’t want the soil to freeze.

What about a greenhouse? If you’ve got the space they have much better light and provide other benefits. “An indoor agricultural evolution is in the making,” according to Food Safety News. “That’s how some people see the surge of interest in growing leafy greens in greenhouses. Because indoor growing is a controlled environment, the farmers don’t have to deal with wildlife, domestic animals, and birds flying overhead — all of which can contaminate the crops.” Indoor growing techniques have advanced so much that about half of all US vegetable production is done indoors. The consumer market for prefabricated greenhouses is strong resulting in a readily available selection of structural shapes and styles.

Commercial agriculture operations likewise use a host of other techniques to protect plants, including high and low tunnels, cold frames, and hoop houses. “From the outside, a high tunnel closely resembles a greenhouse—it is constructed of the same galvanized steel hoops and polyethylene covering,” according to Keith Stewart author of It’s a Long Road to a Tomato. “But it is not likely to have a fan or heater, and the plants inside will not be growing in trays—rather, they will be growing in the ground and will remain there until harvested. For ventilation, a high tunnel will have sides that roll up about 4 feet along the entire length of the structure, allowing outside air to flow through when temperatures on the inside get too high.”

DIYers can duplicate these structures with clear greenhouse plastic on a pergola or other structures during the cold months and then remove and store them until next winter. Greenhouse plastic properties to consider include, durability, light diffusion capacity, and UV stabilization. Thin greenhouse plastic is less durable and doesn’t last as long as more expensive thicker woven greenhouse plastic. It’s all spelled out on their online shops. AgricultureSolutions.com is one source with price ranges from $0.07 to $0.34 per square foot.

For many plant lovers, the grow light is preferred to the greenhouse. Grow light systems include Fluorescent, Compact Fluorescent (CFLs), Light Emitting Diodes (LEDs) Incandescent, High-pressure sodium (HPS) and metal halide (MH). Choose the appropriate light for your application. There are grow lights that emit the light spectrum best suited for each stage of the plant life cycle including seed germination,vegetative growth, flowering and fruiting stages. For general use, propagation, and growing seedlings, the full-spectrum LEDs are best for plant health with a low energy draw as they aren’t creating heat. They are good for all phases of plant growth whereas others specialize in only a particular phase of growth.

Growers House provides a comparison and review test using laboratory data to identify the best LED grow lights of 2021 and what you need to know to get the most for your dollar and indoor plants.

For more information contact our staff with any additional overwintering and indoor propagation questions. We are here to help you achieve your indoor and outdoor gardening goals. And for comprehensive solutions to your specific lawn, garden, and landscaping needs, contact Earth Works of Jacksonville online and at 904-996-0712.
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