(And impatiens, begonias, oregano, rosemary…)
Q. Dear Mike: Years ago, when I subscribed to ORGANIC GARDENING magazine, you wrote about bringing your pepper plants in for the winter and transplanting them back into the garden the following Spring. My brother has a few choice plants I am interested in "wintering over." Could you repeat the specifics of how this is accomplished? I still miss you as editor of OG—I learned much from the magazine. Regards,
- ---David in Middleport (Schuylkill County), Pa.
Q. Dear Mike: I grew bell pepper plants this summer in 17" containers. I've heard you mention that you bring yours indoors each winter and grow them under fluorescent lights. Am thinking of doing the same. But you've said that you get peppers only until around Thanksgiving. Why can't you get them to continue producing through the winter? Thanks; your show is the best!
- ---Bruce in Norwood, Pa.
A.'Dank you, boys—this is one of my favorite tricks! Yes—peppers (hot and sweet) are perennial plants that will live for many, many years if protected from frost.
If your pepper plants are in the ground, transfer them into pots right away. I like to fill such containers with a mix of 1/3 compost and 2/3 loose, seed-starting mix when I'm starting out fresh, but we don't want to stress these puppies with a lot of repotting. So just dig a circle around each plant with a sharp shovel, pop it out of the ground with enough dirt attached that no roots are showing, and slide it into a big plastic (NOT terra cotta) pot. Do this in the evening; never in the morning or heat of the day.
If the Island of Earth you have excavated is a little too big, shave dirt off the sides till it fits. If there's room for more soil inside the pot, add some compost, not more garden soil. Then water well and put the pots in a shady spot for a few days.
If your plants are already in pots, pick up here.
LONG before frost (while nighttime temps are still in the 50s) rinse the plants off REALLY well in the garden with sharp streams of water. Wait a few hours, move the plants to a different spot in the garden and repeat. Then bring them inside to a porch or other appropriate in-between place, wait a day or two and inspect the plants well for aphids and other pests. If you see any, rinse them in the tub or shower twice; one day apart. If you see no pests, do it once.
Then place them directly under a "shoplight"; that means a fixture housing two, four-foot long, 40W Cool White florescent bulbs. NOT "plant lights"; like me, these theoretically-perfect plant growers are just too dim. Always keep the tops of the plants almost touching the bulbs—the light intensity of these fixtures drops off dramatically after just a few inches, and florescent light is cool, so closeness doesn't harm the plants.
I've always left my lights on 24/7. If that makes you nervous, you can turn them off for a few hours every night. Peppers like it warm, so don't let the temp drop below 55°. A range of 60 to 70° is ideal.
Do not feed the plants, and water only when the pots feel light. This will ripen up any green fruits, and then keep the plants alive till next Spring, when you will be putting those big honkin' puppies out in the garden instead of the puny little starts your neighbors will be buying at the garden center. These big plants produce ripe peppers FAST!
Now, you can keep your plants flowering and fruiting over the winter if you provide warm temps and REALLY bright light. That means:
- A fixture with FOUR, four-foot florescent tubes,
- A two tube fixture sitting overtop of plants that also receive very bright light from a sunny South-facing window,
- Or high-intensity lights like sodium vapor or metal halide (which give off lots of heat—keep all plants several feet away from such lights).
If you choose to do this, provide food and water like it was during the summer and enjoy the peppers.
Oh, and this trick works even better with impatiens and begonias. (I have one pot of impatiens that's at least four years old!) And because these pretty perennial posies are shade-lovers, they don't need a lot of light. Just put them under a two-tube fixture or sit them in a sunny window and they'll bloom most of the winter, providing great indoor color and BIG plants for the Spring—both for free!
Q. Mike: I am growing oregano, rosemary, lavender, sage, and lemon thyme. I need to know which I should just harvest and be done with, and which will survive a Philadelphia winter. Or could some be transplanted into pots and kept in the house until spring? Thanks,
- ---Jennifer in Drexel Hill, PA
A. Mediterranean plants like true oregano (as opposed to the VERY similar looking marjoram—a difference that would take an entire column in itself to describe) and rosemary will survive winter nicely in the heart of a zone 6 city like your nearby Philadelphia (witness the rosemary TREES in inner-city community gardens like the ones near South Street), but they will succumb to frost just a few miles away in the suburbs. I have tried to over-winter rosemary in my zone 6 country garden by growing cold-hardy varieties like "ARP" (which simply becomes the last rosemary in my garden to perish over the winter) and building leaf-filled cages to place around them like fig trees. They always died.
Then I started bringing them in like my pepper plants and they do just fine. So pot yours up—that oregano too—bring them in, and treat them like peppers. They'll go a little dormant, so be careful not to over-water—wait until the pots feel light.
Our listeners in zone 7 and warmer have little to worry about here. Their "tender perennial" herbs do just fine outside—if they remember to water during long dry spells (that's three weeks to a month without moisture). Yes, water them in the winter; they're dormant, not dead. (Unless you don't water them, that is…) Seriously, the typically un-humid air of winter can wick a lot of moisture out of small plants, so give them a drink if winter is dry.
The lavender depends on what kind you have. 'English' is hardy in zone 6; the French and Spanish strains are not. If you're in zone 7 or warmer, any lavender should do fine outdoors. Common and 'clary' sage are hardy down to zone 5; but the fancier ones die outdoors in gardens colder than zone 7.
Some low-growing thymes, like creeping and wooly, do well almost everywhere outdoors. But your lemon thyme—one of the premier natural mosquito repellants—is tender, so bring it in. In the Deep South, you can just leave it outside—but you already knew that.