Tending to Parched Indoor Plants

The air in most homes becomes extremely dry as furnaces force warm air through the rooms. It’s not unusual for relative humidity (RH) inside the home to drop to 15 percent during the winter heating season. Most houseplants do best at about 35 percent to 45 percent RH.

Keep in mind that most houseplants are outdoor plants in their native climates. Tropical and subtropical species can be damaged by temperatures below 50 F, but being too warm in winter can also be a problem.

Warm indoor temperatures coupled with low humidity can cause plants to lose water faster than they can take it up. So, even though the soil may hold plenty of moisture, the leaves may begin to droop or turn brown along the edges. (Hot, dry, stale air also creates a favorable environment for spider mites to become troublesome.)

The most effective way to increase RH for the comfort of both plants and people is to run a humidifier. Grouping plants together on pebble trays filled with water can also help. However, misting plants occasionally with a spray bottle adds such temporary moisture that it does not effectively change the relative humidity. Keep all plants away from hot air drafts near heat registers. Ferns are especially sensitive to dry air, so take care to place them in a protected area.

Although some plants may grow more slowly during the short days of winter, dry air can cause them to need to be watered even more frequently than when they were actively growing. Monitor the soil moisture to be sure that plants are getting watered as needed.

B. Rosie Lerner is the Purdue Extension Consumer Horticulturist at Purdue University, West Lafayette.

Save the Seed!

If you didn’t use up all of the garden seed you bought this year, much of it can be stored for use in next year’s garden, depending on the plant species. Seeds of some plants, such as corn, parsley, onion, viola (pansies), verbena, phlox, and salvia, are not very long lived, lasting only one or two years at best. Other seeds, including beans, carrots, lettuce, peas, radishes, snapdragon, cosmos, sweet William, and zinnia will remain viable (capable of germinating) for three to five years.

Seeds need to be kept cool, dark, and dry so that they retain stored carbohydrates and minimize fungal infection. You can keep the seeds in their original packets to preserve their labeling information. If you transfer the seeds to another container, be sure to label them with at least the plant name and the year the seed was purchased. Either way, be sure the seed is as dry as possible before placing in storage.

One of the more practical methods for storing small quantities is to place leftover seed in sealed jars or other airtight containers and store in a cool, dark area such as the refrigerator (not the freezer). A layer of powdered milk or uncooked rice at the bottom of the container will absorb excess moisture. Use a paper towel to separate the seed from the absorptive material.

These days, many seed packets only contain a few seeds so the germination test may be a moot point! On the other hand, many seeds are pricey, so saving even a few seeds can make a big impact on next year’s gardening budget.

The following chart listing storage life for common garden species will help you decide which seeds are worth the trouble. However, the conditions in which the seeds are stored dramatically affects how well they will germinate next year, as much or more so than their species.


Plant Expected Storage Life (Years) Under Favorable Conditions
Bean 3
Beet 4
Carrot 3
Corn, sweet 2
Cucumber 5
Kohlrabi 3
Lettuce 6
Muskmelon 5
Okra 2
Onion 1
Parsnip 1
Pea 3
Pepper 2
Pumpkin 4
Radish 5
Spinach 3
Squash 4
Tomato 4
Turnip 4
Watermelon 4

* Knott’s Handbook for Vegetable Growers

Annual Flowers**

Plant Expected Storage Life (Years) Under Favorable Conditions
Ageratum 4
Alyssum 4
Aster 1
Calendula 5
Celosia 4
Coleus 2
Cosmos 3
Dahlia 2
Dianthus 4
Geranium 1
Hibiscus 3
Hollyhock 2
Impatiens 2
Lobelia 3
Marigold 2
Nasturtium 5
Nicotiana 3
Pansy 1
Petunia 2
Phlox 1
Poppy 4
Salvia 1
Verbena 1
Vinca 1
Zinnia 5

** Hill Gardens of Maine,

B. Rosie Lerner is the Purdue Extension Consumer Horticulturist at Purdue University, West Lafayette, Indiana.

No Leaf Left Behind: 7 Yard-Prepping Tips for the Season

As the growing season comes to a close, there are still a few more chores that call the gardener to action. Mowing, watering, pruning, and cleaning continue to beckon. But it’s important to prepare your yard for the upcoming season. Here are seven ways to make sure your yard doesn’t “fall” apart.

Keep on mowin’
Lawns need mowing as long as the grass continues to grow—some years continuing through most of the fall. Newly planted flowers, trees, and shrubs should be watered thoroughly every week or so, right up until the ground freezes, especially if rainfall is lacking. Perennials, trees, and shrubs all continue to lose water through the winter, so you want them to go into dormancy with plentiful moisture.

No leaf left behind
Fallen leaves should be recycled, either where they fall or transferred to another spot. Dry leaves can be mowed to bits, gathered for use as winter mulch, or raked to the compost pile. Small leaves such as honey locust may be left as is, but larger leaves such as oak and maple should be shredded to speed decomposition and prevent smothering.

Don’t prune out
Trees and shrubs should be assessed, but fall pruning should be restricted to removal of only dead or damaged limbs. Save major pruning chores for late winter.

Don’t be a fool, clean your tools
Winterize your gardening tools as freezing temperatures become the norm by first giving them a thorough cleaning. Those steel wool scrubbing pads sold for cleaning barbeque grills are great for removing caked-on soil from shovels, hoes, trowels, and spades. Scrub the blades and handles with soap and water, and allow them to dry completely before storing. Rub a little linseed oil or similar protector over wood handles to keep the wood from drying and splitting.

Be the sharpest in the shed
Sharpen your tools now to ensure a quick start in spring when your gardening enthusiasm returns anew.

Drain water from garden hoses and sprinklers, and hang them to dry before coiling the hoses for storage. Hoses left outdoors during the winter are likely to crack and split, especially if they still have water inside. And while you’re at it, now is a good time to replace washers and repair leaks while they are fresh in your mind.

Caution: hazardous material
Rinse and dry your fertilizer spreader and oil moving parts. Pesticide sprayers should be rinsed and allowed to drip dry before storing. The best way to dispose of unused chemicals in the sprayer is to apply the product as directed on the label. Allowing pesticide to sit in the sprayer over winter will result in clogged hoses and nozzles and will be more difficult to clean after the fact. Store unused pesticides in their original containers with the label intact. Place all pesticides away from children’s and pets’ reach in either a locked cabinet or a storage shelf at least 4 feet off the ground and protected from both freezing temperatures and excessive heat.

Winterizing the lawnmower
When you are fairly certain your lawn has seen its last mowing for this season, it’s time to winterize the mower. Check local service providers for those that offer mower winterization or use the following checklist to do it yourself. Check the owner’s manual for your specific machine before you start.

—Drain or stabilize the fuel. You can either run the mower until it is out of fuel, or fill the tank and add a stabilizer product. If choosing the latter, run the mower for a few minutes after adding the stabilizer to allow it to reach the carburetor.

—Change the oil and dispose of used oil properly. Your local recycling center or solid waste management district office can advise.

—Clean the blades/mowing deck. Scrape off caked-on debris using a barbeque scrubber; use thick leather gloves to protect your skin from cuts.

—Charge the battery. If your machine uses a battery, charge it now and repeat periodically through winter.

—Lubricate moving parts. Check owner’s manual for specifics.

—Change plugs and filters and sharpen blades. These can wait until spring, if preferred.

Ah, now it’s time to enjoy some well-deserved R&R curled up next to the fireplace with your favorite gardening book!

B. Rosie Lerner is the Purdue Extension Consumer Horticulturist at Purdue University, West Lafayette, Indiana.