Summer is long gone, and even late season harvests are winding down on balconies and in backyards everywhere. Now its time to get growing indoors, which means dusting off the equipment, setting up your grow room and sowing some new seeds for fresh winter vegetables. How’s your grow light situation?
Some people might be able to rely on the sun, but for many the next few months will bring more cloudy skies than clear. Even if you’re gearing up for a windowsill garden, your plants will be a lot more productive if you provide them with lighting assistance. Winter sunshine is not the same as it is through spring and summer either. Plants can’t be lied to about that, in fact, it’s hard to lie to a plant about anything. The results are always disappointing to devastating… depending on the manner of your attempted tomfoolery or unfortunate misunderstanding.
1) Morning Regularity
It has to be like clockwork – always on time. If you start your young seedlings on a 7:30 a.m. sunrise, because that’s when you get up and switch on their lights, don’t change up on ’em later on. It’s not okay if you forget to hit the light switch on the grow light until after a cup of java kicks in. You’re mucking up the meal preparation and dining schedule. They can’t be late for dinner, and no, your apologies will not provide an equitable solution.
Most plants need 10-12 hours a day under grow lights in the vegetative state – that starts and stops at the same hour every day. They don’t like sleeping late on Saturday, because they’re not sleeping, they’re eating, and totally out of food at the appointed sunup time. Buy a timer! An inexpensive mechanical light timer does the trick very reliably. Something like THIS ONE from the big orange box.
2) Capture It All
Most indoor winter gardeners want efficient grow lights, so they opt for CFL, HO T5, or XHO T5 fixtures. But even if you’re running something stronger, you won’t want to use any electricity that isn’t being used by your plants. That’s pretty wasteful, and inefficient, not to mention cutting your garden short of sorely needed light energy. With taller canopied plants, only the tops of them will get light with all of it coming from overhead. This creates sort of a forest effect where it’s shady below the tree tops, which will make your garden resemble one too. Tall thin plants with no action lower on the stems.
Getting more light power out lower energy consuming lights means not letting it escape. Bounce it back – from the walls and floor with reflective surfaces. White walls are good. Shiny white is better. But metallic will make a big difference. Silver mylar is nice, but pricey. Tinfoil, however, is cheap. Tape it on the walls and floor of the grow room at the very least, and on the ceiling if it’s not too far above the fixture. This will bounce the light back at the plants and help do away with the dark shade beneath tall plant crowns. Obviously you need walls around your indoor garden to make use of all the grow light energy delivered. Don’t have sides? Make some! Cardboard, cheap paneling… you’ll come up with something, and besides, this helps keep the environment easier to control.
3) Get The Spacing Right
The distance between the top of each plant and the grow light is beyond important. Just like you wouldn’t expect strong sunlight 5 feet away from a southern window, too much space between the lamp and the garden canopy never works out. With efficient grow lights – CFLs and T5s – never have your lights more than 4 inches above your plants. Don’t let the top leaves get too close though. Check the spacing every morning, and adjust it accordingly. If you’re using and HID light then you want to keep it at 12 inches above the canopy.
It’s best to hang grow lights on a chain for this very reason, so it’s easy to move them up and down in set increments. Connect the light hanger cables built into the fixture to the chain with an S-hook, if it didn’t come with one already attached. They cost like 10 cents each at your local hardware store.
4) Don’t Be A Light Miser
Plants have no concept of your utility bills. They need light to create food. Wimpy light makes wimpy energy, which never converts into an ample harvest. Use a grow light. It’s not about lumens, its about replacing sunshine, which enters the PAR zone. Trying to create good PAR for plants from home light bulbs is impossible. Those are for humans, not gardens.
The timer in #1 will help you keep your garden’s energy use on a strict electrical diet. But you also need to have good overhead light intensity for all the plants you’re growing. The light from CFLs and T5s falls straight down, which means that plants beyond the fixture edges are getting less light. Don’t try to space your grow lights more than a few inches apart. Unlike the sun, this light doesn’t reach sideways.