If you’re new to growing from seed or received a window sill gardening kit for Christmas and are itching to get a start on your herb garden and tomatoes, do yourself a favor — put your seeds and potting soil back in the box and consider putting your energies towards growing microgreens or sprouts for the next six to eight weeks. Unless you’re lucky enough to have a heated greenhouse or a basement setup with expensive grow lights, it’s way too early to begin growing plants for the garden.
Giving plants a strong head start is key to achieving success, so if your seedlings are weak and spindly, even if they do survive to be planted in the garden they will probably never reach their genetic potential.
Light and humidity are the big limiting factors when starting seedlings indoors in winter. As they grow, to keep seedlings from stretching and becoming weak and spindly they need more light than even a south-facing window in winter can provide. Two standard fluorescent lamps placed a few inches above a nursery tray of seedlings will suffice, but as the plants grow full spectrum lighting will be needed for healthy growth. And if the plants are crowded together and shading each other and their own lower leaves from the light they will not thrive. Remember, plants make their own food through photosynthesis and no amount of fertilizer will make up for lack of sun or light.
A humidity dome (it could be an inflated plastic bag) placed over the seed tray will keep the humidity at about 98 percent, ideal for sprouting seeds. Once all the seeds have germinated and started to grow it should be removed to prevent mold and disease.
My late partner, the Yardener Jeff Ball, and I always had good luck starting our tomatoes and pepper seedlings around the last week in March in Lapeer County.
However, morning glory, nasturtium, melons, cucumber and squash resent transplanting and are best started about 4 weeks prior to transplanting outdoors. Many gardeners prefer just to start these from seed planted directly the ground. Either way, be sure the soil has warmed to 60 degrees F.
Quick Tip: Soaking the seeds in liquid kelp, aka seaweed fertilizer, about 8 hours before planting, at a rate of a couple of drops per cup of warm water, will fast start and increase seed germination.
Nancy Szerlag is a master gardener and Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to Yardener.com and click on Ask Nancy. You can also read her previous columns at detroitnewscom/homestyle.