Creative Lighting for Seed Starting

As we get close to the time to start tomato, pepper, and other seedlings indoors, I thought I’d share this picture of my older sister’s seed starting setup from few years ago:

lamps et al

Two desk lamps with compact florescent bulbs. Not traditional, but worked great. Just a reminder that you can get creative when it comes to lighting for seedlings, using whatever fixtures and layout works for your space. The only rules are to use florescent or LED bulbs, not those old fashioned incandescent bulbs which have poor light for plants, and err on the side of more light rather than less to make sure you get compact, healthy plants that will transition to the sunny outside world without drama.
Joseph Tychonievich

 

Why you (probably) shouldn’t be starting seeds yet

As a beginning gardener I learned that to give plants like tomatoes and peppers more time to grow and produce the largest possible crop, it was best to start the seeds early indoors.

gazaniaseedlingsAs soon as I learned that, I wondered: Well, if starting my tomatoes 6-8 weeks before transplanting them outside is good, surely 10 weeks would be better, right? Or 12? Or 16?

Turns out, earlier isn’t always better, and here are some of the reasons why.

First, you probably don’t have enough light. If, like most home gardeners, you are starting seeds under florescent bulbs, it is difficult to give sun lovers like tomatoes and peppers enough light. Light intensity drops off rapidly as you move away from the bulbs, so you know to keep the bulbs right above your seedlings. This works great when the plants are small, but as they grow it becomes very difficult to give both the tops and the bottoms of the seedlings enough light. The result is dying lower leaves and spindly, unhealthy growth.

rootboundSecondly, you are almost certainly going to get some crappy root systems. If you’ve followed this blog for a while, you’ve no doubt read Bert and Linda talking about all the potential problems with the root systems of container grown trees and shrubs. Well, most of the same problems develop with other plants grown in small containers. The roots start circling and they are slow to grow out of the rich soil of the container and into the native soil around them once transplanted into the garden. The longer your transplants grow indoors, the more likely they are to develop problematic root systems. Keeping transplanting them up to larger and larger containers can help mitigate the problem, but that quickly takes up far more space than most home gardeners have for there seedlings.

How big and impact that circling root system will have on the health of the plant varies by species. My personal experience growing zinnias, for example, is that they handle circling, pot-bound roots so poorly that plants from seeds sown directly in the garden quickly over-take and out-perform plants started weeks earlier indoors.

So follow the recommendations for the timing of seed starting. It really does work better. You should be able to get advice on when to start seeds from the catalogs you are shopping, extension offices, or you can use Margaret Roach’s excellent seed sowing calculator.

If you DO decide that earlier is better, that you can provide the light and generous pot sizes to avoid problems, there’s no harm in giving it a shot. But if you do, try starting a second batch at the later, recommended, time and growing the two side-by-side in the garden so you can really compare and see which perform best in the actual conditions of your garden, and if all that extra time and space under your lights or in your greenhouse was really worth it.

Joseph Tychonievich

Cold Stratification for seeds

You may think of spring as the time for seed sowing, but I do a lot of seed planting now, in the fall. The reason is that most of the cold hardy perennials, trees and shrubs that I like to grow produce seeds that require cold stratification.
This simply means that they require a period exposed to cold temperatures while the seeds are moist and hydrated before they will germinate.

The requirement for cold is a pretty straight-forward adaptation to life in cold climates. Seeds that ripen in the summer and fall might not have time to get established before winter if they germinated right away. The requirement for cold means the seeds don’t actually sprout until spring, giving them a full growing season to get ready for the next winter.

seedbed
An outdoor seed bed is an easy way to stratify seeds

You can — and I used to — give seeds this cold period in the refrigerator. Three months in the fridge in a plastic bag with a damp paper towel to keep the seeds moist is long enough for most everything, though the exact period of cold required varies by the plant. The fridge works, but I think it is way easier to just do it outside. So the past few days I’ve been busy sowing seeds out in my outdoor seed beds. They’re just raised beds, filled with potting media, and covered with a screen lid to limit the number of weed seeds that blow in and keep disruptive animals out. I plant my seeds in the fall. Come spring, after the seeds have had their dose of cold, they sprout.

Dianthus seedlings ready for transplanting
Dianthus seedlings ready for transplanting

Once the seedlings have grown on a while, I dig them out, separate the individual plants, and put them out into their final locations in the garden.

Individual seedlings separated and ready for planting
Individual seedlings separated and ready for planting

I do this with more and more seeds every year, even for perennials that don’t require a cold period to germinate, simply because it is so easy. No fussing around with lights or checking the calendar or even much watering. Just plunk the seeds in, and dig out the plants once they are big enough.

Cactus grafting fun

I’ve been grafting cactus this summer, and made this:

grafted cactus

It is a seedling of the gorgeous hardy cactus Echinocereus reichenbachii, grafted onto Pereskiopsis spathulata, an odd, leafy cactus I wrote about earlier.

Why do this? Other than the fact that it is darn cool? Well, because that vigorous, fast growing rootstock pumps a lot of energy into the cactus grafted on top, making the grafted cactus grow a LOT faster than left on its own roots.

grafted cactus startThis is a (terrible, blurry) picture what the graft looked like when I first made it back in July. Just three months later it has grown to enormously, while the seedlings I left on their own roots look pretty much the same. I’ll let it grow on the graft for a while, then probably next year some time, cut it off, and move it into the garden, getting me to a reasonably sized plant in a reasonable amount of time.

So… if you want to speed up the growth of a pokey cactus, try grafting it. The process is crazy easy, lots of fun, and very thoroughly explained here.