Seed-Starting Overview (part two)

Photo of oak trees in winter

 

A reasonable schedule in zone 6b might be to start perennials, herbs in the mint family (many of which are perennial), and anything the packet says takes longer than eight weeks to reach transplant size, in late February (Feb. 25th for me). Start annuals with six-to eight-week maturing periods in March (March 10 for me). Start quick (2-3 weeks) annuals and vegetables, that will only get leggy indoors, in early April (April 1st for me). Also, you can do succession sowing to get later swaths of zinnias, marigolds, salvias, snapdragons, etc., ready to flower in late summer, as late as the first week of May. The reason for sowing anything in flats that can be sown directly is to get size on the plant, and make it less vulnerable. Corn is a good example—a sprouted kernel to a squirrel is just a snack with leaves attached, that need biting off. If you grow your corn in pots until the kernel is used up, and the roots are strong, you may get a harvest for yourself.

Last year I got too eager to grow things, and started perennials in January. I was also trying to use a potting medium instead of peat pellets, and it messed up my germination rate. I don’t find it as easy to go peat-free as the TV garden shows imply. The peat pellets’ advantage is that they’re resistant to fungus, and the protection they offer lasts a long time, until the seedling has grown past the danger of wilting. Also, they can hold moisture without heaviness. Heavy damp stresses seeds for oxygen, and more humus-y mixes retain cold, both inhibiting factors to germination and survival. Last year, many of my seeds never germinated at all.

Another problem with keeping plants indoors too long is the artificial environment. Indoor air is stagnant, allowing a foothold to disease, fungus gnats, and mites; plants need air movement for transpiration, the release of moisture through the pores in their leaves, which encourages the root system to draw moisture from the medium. In fact, a fan running in your growing room, at low speed, is a good idea.

The time when your plants are large enough to go outdoors should coincide well with the change in weather, from winter cold to spring daytime temps in the 60s and 70s. Find a shaded space with wind protection, or create one. Perennials should be first out; once they can stand on their own in full sun, and especially with the benefit of a few rains, you can take them out of circulation—either plant them, or at least place their pots where you intend to plant them. A number of perennials, such as coneflower, salvia, achillea, rudbeckia, monarda, and foxglove, have hairy, rumply, or ferny leaves, a sign that they’re adapted to frost tolerance.

Frost, also, harms hardy plants less after the equinox (March 20, 2023)—when daytime length equals night. Nighttime temps in zone 6b are usually above freezing. The ground warms up, and the hours of frost needed to burn leaves and harm roots are not available. Observe which plants already in your garden are pushing up strong new growth; the same plants from this year’s starts will survive through frost, if you have them well hardened.

 

(to be continued)

 

Seed-Starting Overview (part One)

Photo of bright yellow coreopsis blooms

 

Photo of seed-starting shelves and lighting

 

January is a good time to get your setup going, if you want to try stocking your garden with seed-grown plants. For the next few posts, I’ll provide what experience has taught me.

Any four-shelf unit really gives you three, unless you have a way of rigging lights above the topmost shelf; but this shelf makes a place to store your gear—spray bottles, pots, labels, etc. The ones I use are sold under the Amazon Basics brand, listed this year at 64.96, not including sales tax. They consist of wire shelves, hollow posts that screw together, and plastic fasteners that hold the shelves in place. They are not very trying to assemble, and also pretty attractive for use at other times as household furniture.

What you’ll want, if starting 500+ seeds (which sounds like a lot, but for any largish garden, is barely enough) is at least three sets of shelves. Each shelf can hold two flats, oriented short end to short end, for maximum exposure to light. When seedlings are large enough to be potted on (as in photo above), fewer will fit in a flat, and the shelves need spacing higher—the reason you need three units, instead of two.

For lights, daylight (blue-toned) LEDs work fine; I have not found any deficit in the light they provide to seedlings. The best choice is the shoplight type (at various stores, around $50 for a set of two), with two tubes per unit, and a four-foot length—and you’ll be happier if you buy lights that connect to one another, so that you have one cord per six lights in your surge protector, instead of a big tangle of cords. You can add up the wattage to be extra careful, but even three shelving units with eighteen lights altogether should fall well short of the load-capacity on a modern household plug.

Eighteen shoplights are a strong investment, true, but once you’ve purchased your seed-starting equipment, the cost-per-year over the lifetime of the equipment is reasonable, and even cheap. If you compare the cost of this same arrangement as sold by garden suppliers (as much as $300 for a two-shelf unit, or $1200 for four shelves), you’ll appreciate that a $700 (approx.) investment for three four-shelf units with lighting is a good bargain.

Any room with a door you can close against curious pets works as a growing room. I use a spare bedroom, and protect the carpet with drop cloths. Even LED bulbs will add heat to the room. I find I can’t use more than the three sets of shelf/light combos without the temp approaching the 80s (F), which is too stuffy for most outdoor plants, especially perennials. I move surplus maturing plants down to the garage. At this stage they’re fine, if not happier, in a cooler space, but if your seed-starting racks can only be in an unheated garage or porch, you’ll need heat mats.

The window of time for seedlings, from dropping the seed into the medium, to hardening off well-grown seedlings outdoors, should be about two months. This formula is usually calculated backwards from your local frost-free date, so that a May 5th date carries you to March 5th. But most perennials take longer than annuals to geminate; at the same time, the majority of perennials hardy in your zone can go in the garden earlier than the frost-free date, once hardened off (exposed to outdoor sunlight and wind until the leaves and roots toughen up). Exceptions are hibiscus and butterfly weed, both of which emerge from the ground after frost, and would be harmed if planted earlier.

 

(to be continued)

 

Little Finds

 

Above are some volunteers, seeded from garden fixtures, or annuals I grew last year. 

The petunia sprouted up in one of the pots I brought in from the patio. It stayed small for a long time, by the drafty patio door, and even struggled when I took it up to a windowsill and overwatered it. I wasn’t sure yet what plant it was. Finally, it got to be time for seed-starting, and putting up the lights and shelves. Once the petunia was warm and pampered, it took off. I usually buy petunia seeds in watercolor patterns, that have the pretty veins. This one looks true-to-type.

In the lower half of the second picture, you can see an impatien that seeded itself, and had picked up genes from both the red and pink ones. It’s producing a Rembrandt tulip effect, with marbleized streaks of color, so that each flower is different. But the overall effect is a coral.

The third picture is of hellebore seedlings. Seemingly, every seed that dropped last year germinated. I have hundreds of them, and literally removed more than a hundred to start in pots. I don’t know what I’ll do with them all, but I can see lining paths with them. The deer don’t bother them, and they bloom in winter, so a little hellebore hedge ought to be a good idea.

 

 

A Pretty Bloom and Some Seed-Starting Info

Photo of blue penstemon-like flower of strobilanthes

 

Strobilanthes dyeriana, the Persian Shield plant common in garden centers in the summer, is native to Myanmar. Some species of Strobilanthes are grown for their flowers, but Persian Shield is used for foliage. One of mine, that I brought to overwinter indoors, has put up dozens of flowerheads. Now some of the blooms are open, and as the photos show, they come out a pretty blue-purple, and with a shape like a penstemon flower, about an inch in length. (The two aren’t related; Strobilanthes is in the Acanthus family, and penstemon is in the plantain family.) 

 

I saw an article last year, in the New York Times where, discussing the collecting and sowing of wildflower seeds, a native plant expert said the Butterfly Weed, Asclepius tuberosa, is difficult to start. I’ve actually had good success with it, so I thought I’d share my method and observations.

I collect a couple of pods, which as you can see gives more than enough seed. I put them in an open container in my garage. When they split naturally, which takes some months, the seeds will puff out from the expanding floss. The floss, once the pods have opened on their own timetable, pulls loose from the seed easily. That makes sense. The seed wants to root itself somewhere, not be carried by the wind forever.

My intuition is that the cold of being in the garage in winter, while it probably matters, is less key to germination than letting the pod reach the stage of splitting, and planting seeds that need no tugging to remove the floss. I sow them like most others, upstairs in my cat-proof room with the lights and shelves, just tucked under the surface of the medium, and I get several new plants going that way.