WICHE: Late start to seed starting

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Here is how to get those seeds to sprout before you plant them in the garden.

By Jeneen Wiche

I generally have seed trays full of little sprouts by now, but this year the lingering cold weather has me languishing, quite frankly. The seed potato and onion sets sit waiting for the soil to dry out a bit, and seed packets glare at me from their neat stack strategically placed on the kitchen work table.

So it is time to gather up all the paraphernalia needed to get the job done, and it probably a good thing that I am behind, because it will be a while before our soils warm to a cozy temperature for summer crops to be transplanted safely.

Cool season starts, like kale, broccoli and Brussels sprouts, can go as soon as they like, once our freezing temperatures are finally behind us. What a crazy March it has been.

My setup is not elaborate. It basically consists of a kit that includes a plastic dome that fits over a seed tray and pan. You can craft your own by using shallow containers (or a shallow flat with drainage holes, like you would get if you bought a flat of pansies). Here’s what to do:

  • Fill the flat with sterile growing medium, like a 50-50 mix of vermiculite and peat moss, and then top it off with some clear plastic.
  • Moisten your germinating mix in a bucket before filling your flat.
  • Take a pencil and make several shallow furrows in the mix, and drop in your seeds (check planting depth on the seed packet; some seeds need light to germinate, so you do not want to cover them with your germinating mixture).
  • Gently moisten again with your spray bottle and cover with a plastic hood or homemade tent (if you prefer the homemade version, use Popsicle sticks to support your tent).
  • Plug in your heated mat, if included. Germination really does benefit from some bottom warmth, especially with summer crops like peppers, eggplant and tomatoes. The plastic covering increases the relative humidity and moderates the soil moisture as the seeds germinate.
  • Open the tent daily to see if more moisture is needed, mist accordingly using your spray bottle. Consistency is necessary for both moisture and warmth.

Seeds need varying degrees of warmth to germinate, so for cool-season crops you may not need any more heat than what a sunny window or some grow lights will provide.

Summer crops will benefit from an additional source, like a heating mat. You don’t want to cook your seeds, just keep them on the warm side. It is not ideal to put them by a heat register or refrigerator because this is an inconsistent source of warmth and dries the seedlings out.

If your tray is in a bright window, you will need to rotate the tray daily once the seedlings emerge. Grow lights overhead are ideal because the seedlings grow stout and straight.

Once your seedlings emerge, remove the covering and begin to water the tray from the bottom to maintain even moisture (not soggy). Once the second set of true leaves form (those that are the shape that you associate with the plant), your adolescent seedlings are ready to be transplanted into their own pot containing transplant mix.

You can use small pots left over from store-bought plants. Once they are transplanted, return them to their light source (if they are in a window, give them a quarter turn every day, so they grow straight). Continue to water your transplants from the bottom when needed, adding some diluted fish emulsion fertilizer once a week.

When conditions are right for your particular plant (check the seed package for details), acclimate them to the outdoors before planting them in the garden. Put them outside in the shade, first, gradually moving them into the sunlight.

They will be ready to plant in the garden in about a week. And remember that soil temperature matters, too. Don’t rush heat-loving plants into a garden that is still shaking off its winter chill.