End-of-season harvest, saving seeds, and winter herbs: This Weekend in the Garden

Make the most out of those year-end veggies

The growing season is heading down the home stretch now, so it’ll be time in the coming weeks to cash in on what’s left in the garden.

Warm-season crops like tomatoes, peppers, cucumbers, eggplants, squash, melons, pumpkins, sweet potatoes, and basil will die with the first hard frost, which according to National Weather Service records, has been averaging Nov. 2 since 2000 in the Harrisburg area.

You’ll want to harvest those crops before a frost happens because that single sub-freezing night will leave behind mushy fruits and wilted, blackened leaves in the morning.

Most fruits will last at least a week or two in the refrigerator, or they can be processed and canned or frozen for winter use.

Green tomatoes showing even a little color will usually ripen on a kitchen counter at room temperature. Or green tomatoes can be fried or turned into relishes and chutneys.

To maximize the storage life of pumpkins and winter squash, the National Gardening Association recommends leaving several inches of stem attached and “curing” them in a warm, well-ventilated spot in the 70- to 85-degree range for about three weeks. Then move them to a cool, dry spot (50 to 60 degrees is ideal) for longer keeping.

In any event, it’s better to pick and give away whatever you’re not going to use than let it go to waste in a frozen-over garden. Food banks and non-gardening friends and neighbors are usually happy to get free fresh produce.

Frost-tolerant crops can be left in the garden to gradually harvest well into fall. With protectors such as cold frames, floating row covers, plastic-covered tunnels, and straw bales, some of those crops can last into winter.

“Throw about a foot of straw over your unharvested root crops before the ground freezes in late fall,” recommends the National Gardening Association. “This will insulate the soil, and you’ll be able to go out into early winter, pull back the covering, and continue your harvest of carrots, beets, rutabagas, and turnips. Extend the mulch out about a foot and a half on each side of the planting.

To maximize the storage life of harvested root crops, NGA recommends digging up the roots after two or three days of dry weather, then curing them in the sun for a few hours.

“Never wash roots before you store them,” NGA advises. “Just cut off the tops right out in the garden. Leave about an inch of stem for beets, so they don’t ‘bleed’ in cooking. For other root crops, cut the tops close. Wash the roots just before using them.”

Defect-free roots keep longer than ones with damage or defects.

“Injuries are avenues for rot that can spread to other vegetables,” NGA adds. “Also, don’t ever clip off the bottom end of the root before you put it in storage. This, too, can open an avenue to rot.”

The ideal storage condition for root crops is just above freezing (34 degrees is perfect) in a dark, humid place. A refrigerator is an obvious setting if you have the space, and so is a root cellar – an unheated but protected storage area that was common in generations past.

How to save seeds

Home-grown veggie crops aren’t the only thing worth saving in the landscape before a hard freeze.

You might also be able to gather seeds of this year’s flowers and vegetables to save for next year’s use.

Some plants are easier seed-givers than others, but anything that you manage to save and start means fewer seeds you’ll have to buy.

Because most plants mature their seed as the season winds down, the next few weeks are some of the year’s best for collecting seeds to save.

The Seed Savers Exchange, an Iowa-based nonprofit dedicated to preserving heirloom seeds, is a wealth of free information on how to do the deed.

Some basic pointers from SSE:

1.) Stick with heirloom or “open-pollinated” varieties, which are types that produce the same (or very similar) traits from year to year.

Many flower and vegetable varieties these days are hybrids, which growers produce by interbreeding two different parents. Seed saved from those might produce a new crop more like one of the parents, something new and inferior, or nothing at all since some saved seed from hybrids is sterile.

Seed packets and plant labels usually tell you if the variety is a hybrid or not.

2.) Wait until the seed heads have fully matured and the fruits or pods are fully ripe before collecting seed. Green, immature seeds won’t sprout.

3.) The best time to collect seeds is on a sunny, dry day. Whether the seeds are damp or dry when you collect them, it is important that they are completely dry before you store them.

Let the seeds dry naturally. Don’t try to dry them by heating them in an oven or microwave. Seeds are living things, and temperatures beyond 95 degrees can harm them or shorten their keeping time.

4.) For best genetic strength, collect seeds from more than one plant. Always select ones with the traits you value the most, ie the biggest fruits or the most vibrant flower colors.

5.) Label your saved seeds, and store them in small envelopes inside a sealed jar in a cool, dry, dark spot. An ideal spot is inside an empty mayonnaise jar in the refrigerator.

Sealed jars inside a kitchen cabinet is also fine if you can’t spare refrigerator space.

Add a small packet of powdered milk, silica gel, or similar drying agent to the jar to help absorb excess moisture.

Most saved seeds – whether they’re ones you’ve collected or whether they’re leftover seeds from purchased packets – will remain viable for at least three years.

The edible exceptions are onions, leeks, corn, spinach, okra, and parsley, which are best used within a year or two. Flowers on the short-keeping end (a year or two) include columbine, milkweed, impatiens, larkspur, coneflowers, statice, and strawflowers.

Seed Savers Exchange details crop-by-crop seed-saving tips on its website.

Fresh herbs for the winter

Once cold weather makes it tougher to grow edibles outside, it’s possible to keep a few things going inside over winter.

Fruiting plants are tough to do inside without fairly powerful grow lights, but some herbs and leafy greens will produce on a sunny, south-facing windowsill. Examples: leaf lettuce, arugula, endive, kale, mizuna, mustard greens, spinach, Swiss chard, basil, cilantro, chives, garlic chives, dill, thyme, parsley, and oregano.

Give plants some additional light from cheapo workshop lights, and they’ll usually do even better. Twelve to 14 hours of run time per day is ideal for lights.

One option is to dig up and pot existing plants from the garden and move them inside before frost kills them or knocks them back for winter.

Basil and parsley plants, for example, can be dug, cut back, and potted. Divisions of clumping perennials such as chives, thyme, and oregano can also be dug, trimmed, and potted for winter growing.

Before taking any plant inside, hose it down well and/or spray with insecticidal soap or horticultural oil to keep bugs from riding along in.

Also make sure the pots have adequate drainage holes in the bottom and are filled with good quality, lightweight potting mix (not dug-up garden soil).

Set trays under the pots to catch drainage and keep water from running onto the window sills, furniture, or counters.

A second option is starting new plants from seed. This works best for leafy greens such as kale, lettuce, arugula, endive, mizuna, mustard, and spinach as well as for annual leafy herbs such as basil, cilantro, dill, and garlic chives.

Start new seeds every few weeks so you’ll have a continuous supply at different stages through winter.

It’s normal for plants to grow a little spindlier or “leggy” inside. That’s due to the lower light, which is significantly less than outside even next to a south-facing window.

Harvesting and/or pinching will help encourage bushiness. Or rig up a light stand if plants are excessively leggy or if you don’t have any good sunny window space.

Another indoor challenge is watering. The slower-growth and lower-light setting means plants won’t be using as much water as outside, so be careful of rotting roots by overwatering. You may need to water indoor edibles only once or twice a week.

Wait until the soil is dry and the weight of the pot is noticeably lighter than water. Then add enough until it runs out of the drainage holes. Dump any water that’s standing in your trays after the draining finishes.

Your goal is consistently and mildly damp soil… never soggy soil

Behind the light and watering issues, a third challenge is the possibility of bugs.

Maybe you’ll avoid bug trouble by buying clean plants, starting your own plants from seed, and using fresh potting mix.

However, it’s not unusual to run into outbreaks of insects such as whiteflies, fungus gnats, spider mites, mealybugs, scales, and aphids.

One option is inserting yellow sticky cards in a few pots. These cards – available inexpensively in garden catalogs, garden centers, and online vendors – attract bugs with their color and then capture them with their sticky coating.

Other anti-bug options include spraying them with insecticidal soap or washing them off with a stiff spray of water in the shower.

Some indoor growers fertilize their plants every week or two with a diluted balanced fertilizer, and some potting mixes are sold with slow-acting fertilizer included.

Don’t overdo it with fertilizers since plant growth is much slower inside over winter than outside in summer.

• More when-to-do-what tips: George’sPennsylvania Month-by-Month Gardening“book