Although hydroponic growing is done in many different media, each medium offers superior control over the environment. So, whether you’re growing in a greenhouse or in your own home, the ability to insulate your crop from the cold outside means a winter crop is a real option.
If you plan to take advantage of winter gardening using a greenhouse or a growroom not attached to the home heating system, then first look into all the alternatives for maintaining temperature economically.
You’ll need to know the growing characteristics of the crop(s) you intend to grow and see that your greenhouse can accomplish this. Depending on where you live, the winter months can bring with them frequent and sustain gray skies. In a greenhouse this means the need for supplemental electric lighting. The type of lighting that you’ll need for your plants will vary greatly, but these options are all easy to find.
Also, since a greenhouse is separated from the home heating system, you’ll require a source of heat. Good pre-planning can make this issue affordable—good insulating glass or Plexiglas can help keep the cost of heat down. Also, newer greenhouse designs include solar heating, which can result in significant energy savings. However, you’ll need to provide an alternative source of heat to solar-heated greenhouses during cloudy periods.
If you have an indoor garden that can take advantage of the warmth of your home (and you have no problem providing adequate electric light), you are all set to grow year round. Know your crop and the light or radiation requirements for it as many crops require different types of light based on the phase of growth. Do some research on the plants you plan to grow ahead of time.
Moving an outdoor garden indoors
Since synthetic light is not free, many hydroponic gardeners would like to take advantage of sunlight when they can. However, winter can often force them to move their crop indoors (for example, when cold weather comes along before your outdoor tomatoes are finished ripening). This is not a problem if you were prepared for it from the beginning.
One of the easiest types of hydroponic systems to relocate indoors would be a soil-based system. A raised bed is really not going to be movable, and transplanting is way too risky. However, a modular system with individual pots that you can easily disconnect in order to move them one at a time is good.
Also, be sure to plan your growing area indoors for this relocation before you get going—you don’t want to discover that things aren’t going to fit at the time you need to take advantage of your indoor area.
You’ll need to grow in individual pots that, when filled, don’t exceed 50 lb. or so. When moving individual potted plants with sturdy saucers, you can easily use a simple luggage dolly to move them and spare your back.
Though hand watering is much more time-consuming, it does lend itself most easily to being relocated. However, if your garden design incorporates automated watering, you might want it to have the ability to easily disconnect and reconnect.
That is, the water tank, pump, timer, tubing and drips need to connect and disconnect quickly and easily. If building your own, take this into consideration from the start. This type of system is also available turnkey if you search for them, and even these pre-assembled systems are not expensive.
There are also a few other issues to consider regarding your outdoor plants themselves. First, your outdoor crop is likely to have some pests and traces of disease that you can’t even see.
As such, do not combine these outdoor plants with others that have been indoors all along. I strongly recommend that you put these plants into their own indoor tent or separate room, and that you use precautions after tending these plants before tending to others that may have been isolated from these risks up to this point (the expense of a tent will quickly be recovered when you consider the expense of a crop loss from disease or insects).
Also, following good cleanliness and isolation protocol for an indoor crop is your best bet. Daily or frequent inspections will also give you a big advantage. Be sure to pick off leaves that show signs of mildew early; often this can be enough to control the disease.
Also, the number of hours that the plants were receiving sunlight outdoors should be duplicated when moving indoors. Certain plants change their growth habits as the hours of sunlight or grow light are changed. Know the crop you are growing and whether your indoor timer needs adjusting. Also, try to initially use an indoor lamp with a broad spectrum of light and avoid making too many environmental changes at one time.
Moving an indoor garden outdoors
If you are thinking about moving plants from an indoor, controlled light radiation environment to outdoor sun radiation, there are many different concerns that need to be addressed. This option is not an easy one and might not be worth the effort, but I want to discuss it just in case.
First, you need to consider the ambient outdoor direct sunlight and temperature. Avoid moving plants to an outdoor setting when temperatures are too high or the risk of a cold snap still exists. And because solar radiation can be so much stronger than controlled indoor lighting, it’s a good idea to use shade cloth (at least as a transition).
The percentage of sunlight that the shade cloth allows is a vital consideration if you plan to do this. Plants can adapt to this higher radiation, but usually do much better if making this adaptation at a gradual rate; hardening the plants off over a period of several weeks can reduce the stress of this change.
Also, higher temperatures and wind will create a demand for greater transpiration of water from the roots to the foliage and fruit. This means extra demand on the root system and more water.
After being moved outdoors, your crop will be introduced to pests that it has not seen or dealt with before. You will need to be on-guard and ready to help if and when this battle begins. Caterpillars are usually a number one enemy of a veggie garden. Don’t wait until you find that caterpillars have eaten up half or more of your precious crop; Bacillus thuringiensis (BT) and spinosad are great examples of safe, organic pesticides that can help.
So, although moving plants has its disadvantages and dangers, it is worth it. You can easily maximize your harvest by utilizing hydroponics, whether your crop is grown completely indoors or moved indoors as the weather demands.
Written by Frank Rauscher
During his many years of service in horticulture, product development and sales, Frank has performed innumerable visits to landscapes to facilitate a correction for struggling plants or assist with new design. He also writes for Southwest Trees and Turf and The Green Pages, is the owner of Garden Galaxy and manages several websites. He has four children and eight grandchildren.