Garden Plot: Advice for gardeners as temperatures drop this weekend

Will a hard freeze liquefy late lettuce?

Renee in Alexandria, Va., has a very timely question. She writes: “I’ve got lettuce, spinach and kale still doing nicely in my garden, but I’ve never grown them before in the fall. Will they survive the really cold weather this weekend, or should I harvest the entire plants on Saturday so I don’t waste them?”

If this is your first year growing fall crops and they’re just sitting out in the open, I would harvest at least some of those greens (especially the lettuce) before the Big Chill hits, Renee. Without some sort of season-extending device, like a cold frame or row covers, even those cool-weather crops might not survive if our ace weather-guesser Doug Hill is correct that skies will be clear when the temps dip into the 20s Sunday night. Cloudy and windy conditions provide some frost protection, while clear skies and light-to-no winds make for the most severe frosts.

If you want to try and save some of the plants, water the ground thoroughly during the day on Saturday and then drape either professional row covers (the biggest brand name is “Reemay”) or sheer curtains overtop of the plants — and make sure they don’t blow off overnight.

An upside-down cardboard box placed over the plants is a good last minute choice, but don’t use plastic unless it’s supported by hoops or other structures that keep it from touching the plants.

And tell Santa you want a nice row cover kit for the holidays. The protection these hoop and fabric enclosures provide will have you picking fresh salads on New Year’s Day!

“Worms” on plants are really caterpillars in drag

Rose in Ellicott City, Md., is still growing greens. She writes: “I just picked some wonderful kale, but had to soak it in water for a couple of hours to remove the green worms. Then I found more worms after it started cooking. How do you get rid of them”?

Those “worms” — and similar creatures like ‘cabbage worms’ and ‘broccoli worms’ – – are devilishly hard to see because they’ve evolved to become the same color as the crop they’re attacking. Although we call them ‘worms,’ they’re actually pest caterpillars. So next season, you can simply spray the plants with the organic caterpillar-killer Bt (sold under brand names like Dipel, Thuracide and Green Step) and the little buggers will die at the first bite without any possible harm to you or other garden life.

An even better solution is to grow your kale (and other cool-weather crops that don’t require pollination, such as lettuce, spinach, broccoli and cabbage) under floating row covers. Row covers are made of a thin fabric that resembles sheer curtains. They’re sold in rolls that you can either drape across the tops of the plants or support with little hoops. The fabric allows air, light and water to reach the plants, but excludes all pests.

And because row covers trap heat, they allow you to extend your picking season of cool-weather crops by a good month or two.

Home-grown garlic is the best for planting

Howard in Arlington writes: “I’m getting ready to plant garlic and have a fair amount of garlic left from this year’s harvest, probably more than we’ll need for cooking. Is there any reason not to use some of it to plant the next crop?”

There’s actually good reason to replant your own garlic, Howie — and your absolute best cloves to boot. By saving the biggest, best-looking cloves from your summer harvest for replanting in the fall, you begin to create your own strain of garlic that’s better suited to your specific growing conditions than any planting garlic you can buy. And by only planting big cloves, your new strain will have much bigger cloves every season. Eventually, you’ll get four huge cloves per bulb instead of 10 tiny ones.

Two suggestions:

  • Try and plant the new crop in a different area of the garden to prevent diseases, such as neck rot, from building up in the soil.
  • Time’s a wasting. Your cloves should have been in the ground a good month ago, so get digging.

Fungus gnats are freeloading in your houseplants

We continue to get lots of questions about little flying buggers in the house. Linette, down in Fort Washington, Md., writes: “I have house plants in several rooms of my home, including my bedroom, and little gnats in all the rooms, as well. I use a popular brand of potting soil and usually purchase the large bag and keep it in the garage. Could these gnats be coming from the dirt? I don’t think they’re fruit flies because vinegar in a glass didn’t capture a single one.”

Fungus gnats are very common houseplant pests, Linette. And yes, they’re living and breeding in your houseplant soil. They occur naturally outdoors, and some probably flew into that open bag of potting soil over the summer. They can even come inside with you when you open and close a door in warm weather.

You can break the cycle and prevent future gnats two ways.

  • Drench the soil with BTI, a natural product sold for fungus gnat control, which is available by mail-order or at hipper garden centers.
  • Cover the top of the soil in each pot with an inch of sand. This will prevent the adults that are flying around from reaching the soil and laying more eggs. It’ll also stop the larvae that are down in the soil from emerging to fly around as adults.

Oh, and you should probably cut back on the watering. Fungus gnats are most common in over-watered plants. Constantly wet dirt is great for gnats and bad for plants.

Takoma Park soon to have the safest lawns in the nation

Thanksgiving is coming up, and I’m sending out a special thanks to dedicated listener Arlene in Takoma Park. Arlene sent me the good news about her town’s new “Safe Grow Zone Act” that will soon ban the application of most herbicides and pesticides to lawns both public and private.

Two working mothers, Julie Taddeo and Catherine Cummings, pounded the pavements, passed out leaflets, enlisted the aid of health-care professionals and organized enough support to convince City Council to pass the new laws, which will make Takoma Park’s lawns the safest in the nation for children, pets and other living things. The act was passed back in July and the prohibition on the use of most lawn chemicals will be phased in gradually, with lawn care professionals having to comply beginning March 1 and homeowners having until January of 2015 to get their lawns off drugs.

Here’s a great story on the topic with all the details and lots of helpful links, as reported on the hugely popular “Garden Rant” blog by Greenbelt’s own Susan Harris.

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