This winter, and even into the spring, I started some seeds in my garage under my new commercial grow light. It worked really well and I am growing marigolds, coleus, tomatoes, African daisies, basil, and more from seeds. It’s a whole lot cheaper than buying plants and I have a much higher success rate with this new light.
When you grow seedlings indoors and then transfer them outside, you have to slowly expose them to outdoor weather conditions. Indoors, the weather is controlled – a good temperature, perfect lighting, and never too much wind. Outdoors, the weather can be much harsher. Seedlings grown indoors are not prepared for such a dramatic change in climate. If you expose your seedlings to the outdoors too quickly, the leaves might burn or the plant could be damaged.
To harden off your seedlings, slowly introduce your young plants to the outdoors.
Traditional Method for Hardening Plants
Place your seedlings in a part-shade or morning sun only location that is protected from the wind. At first, you do this for an hour the first day and then put them back indoors. Increase the time outdoors slowly (add about an hour each day) for about a week. Be sure to not put them outdoors when the weather is too cool or when there is a strong rain.
Easier Method for Hardening Off Seedlings
But if you want to harden off your seedlings the easy way, try putting them outdoors covered by the top half of a translucent milk jug. You can use the opaque ones too, but the translucent ones seem to let in a little more sun.
On days when it is chilly, you can put the cap back on top of the jug for a little extra warmth (just make sure the temperature doesn’t go below freezing, as the thin plastic isn’t enough protection). The jug lessens the intensity of the sunshine and protects the seedlings from wind and cool temperatures. It’s almost like a miniature greenhouse.
Start by keeping the jugs (with the cap off) on top of the seedlings all day, then slowly expose the seedlings to morning sun and temperatures – for about an hour or so. Gradually increase their exposure over a week or so.
I used the milk jugs on my seedlings this year, keeping them on the seedlings for about a week before exposing them to the elements. They are not the prettiest thing to have sitting in your garden – but it certainly saves on the time and energy it takes to bring the seedlings in and out of doors each day, which makes gardening that much easier. Anything that makes gardening easier, is a good thing.
The seedlings have been doing really well after taking the jugs off and I can handle the eyesore in exchange for the added ease.