So you’ve tried the winter sowing method and found out that it’s easy and it works. Mother Nature woke the seeds out of their sleep and now you’re getting lots of little seedlings popping up in their snug, cozy containers.
Winter Sown Lettuce Seedlings
So now what?
Although winter-sown seedlings at this stage are already much hardier than seedlings grown indoors simply because they have already been acclimated to the outside temperatures, there are ways now to ensure that your seedlings not only survive but thrive in their container until they’re ready for transplant.
Here are some of the most important considerations.
Winter Sown Containers in Sunnier Early Spring Area
In Early Spring
It wasn’t critical where you placed the winter sowing containers in the winter while the seeds awaited Mother Nature’s cue to germinate, but now that some of your babies are “hatching” (usually seeds of cold-hardy plants will germinate first,) container placement becomes more important.
It can still get pretty cold in early spring, especially at night, so a south-facing area that gets some sunlight to warm up the container is ideal.
It’s important now to check the soil to be sure it’s draining properly and add more holes to the container if necessary. Above is the amount of holes I normally drill into the milk jugs. Young seedlings’ roots are small and can rot in soggy soil. At this time, the containers will only need watering if the soil is very dry.
Early Spring is also the time to be cautious about late unexpected freezes, frosts or just unusually cold temperatures. Throw a blanket or cardboard over the containers overnight for extra protection if colder weather is expected.
In Mid Spring
As the warmer weather begins, your seeds of heat-loving plants are beginning to germinate. The soil begins to dry out more quickly now, so caution now turns to making sure you check the soil for dryness. It may only take some top spritz of water early on to keep the seedlings happy.
Moving the containers to a half shade/half sun area is ideal now.
Tops off and bottom watering
In Late Spring, Early Summer
As the heat of summer arrives, if the seedlings are not ready for transplant, it’s a great idea to open up the container for more airflow. You can do this in a variety of ways. Cut out a little window in the front or sides or cut the top off completely.
The soil will need more water now, too. If the seedlings are still small, top watering could dislodge the seedlings from the soil. If you have several containers, a great way to water them is to bottom water several containers at one time. Let the containers soak in a few inches of water for ten or fifteen minutes, then take them back up.
If the potting soil you used has some starter fertilizer in it, you may not need further fertilizer while they’re in the containers. If you used something without starter fertilizer and the seedlings look weak or are struggling, you can give them a feeding of one-fourth strength balanced fertilizer for a little boost.
Whether you need fertilizer or not will also depend on how long you keep the seedlings growing in the container before they’re transplanted.
Cucumber Seedlings Ready for Transplant
When the seedlings look healthy and are strong enough to be handled by their stems, you can transplant them into their final garden space. If you’re in doubt about whether they’re ready for that, let them grow on.
As different plant types grow at different speeds, there is no general recommendation for transplanting time. Seedlings of cucumbers and other cucurbits grow quickly, whereas seedlings of Basil and lettuces grow slowly. As long as the seedlings are happy and healthy in the container, there’s no rush to transplant.
Transplanting on a cool, cloudy day is always best. If it’s a sunny day, you can always put a cardboard tent over the transplants which give them respite from the sun and is still open at the sides for airflow. I have left this shelter on for over a week at times.
So that’s it. Really nothing to it once you get the hang of it.
With some careful attention during the first stages of growth of your winter-sown seedlings, you can ensure those seedlings will grow into healthy plants that will be a great addition to your garden!