Starting seeds indoors is a great way to get started on the gardening season. However, the key is to do it at the right time. The excitement of the upcoming planting season can make it difficult to wait, but starting seeds too early can have several unintended consequences. According to gardening experts, this is the ideal time to start seeds indoors and why you shouldn’t try too early.
Meet the expert
- Tammy Sons is the founder and CEO of TN Nursery.
- Carrie Spoonmore is the co-creator of From Seed to Spoon, a garden planning app by Park Seed.
When should you start seeds indoors?
The exact time to start seeds indoors varies by region, but as a general rule, you should aim to start seeds about six to eight weeks before the last frost date in your area, says Tammy Sons, founder and CEO of TN Nursery .
While the last frost date is always an estimate, it gives gardeners a date to work against. A quick Google search can help you learn the last frost date in your region, which varies by climate and USDA hardiness zone. This means that gardeners in warmer climates can sow earlier than gardeners in colder climates with longer winters.
Some seeds (such as cool-season crops that thrive in cooler temperatures) should be started indoors just a few weeks before the expected last frost date, says Carrie Spoonmore, co-creator of the From Seed to Spoon app. This is because these plants can be transplanted outdoors as soon as the soil becomes workable, even as tender seedlings.
However, some crops such as carrots, radishes and beans do best when sown directly into the garden after the danger of frost has officially passed, says Spoonmore.
Fortunately, you don’t have to remember these details to make sure you get your seeds started at the right time. Seed packets contain all the information you need to successfully start seeds, including recommended starting date, seed planting depth and spacing, recommended light and temperature levels, and more.
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Risks of premature seed initiation
So what’s the problem with seeding earlier than the recommended six to eight week benchmark? Problems arise due to adequate care of mature seedlings indoors.
“Starting seeds too early can cause plants to outgrow their containers or become root-bound, tall or stressed due to lack of adequate light or indoor space,” says Spoonmore.
Once seedlings become leggy or stressed, this process is impossible to reverse, making it much less likely that they will survive when moved to the garden.
Plus, the extra time indoors can make the transplant process itself more complicated, Sons says. Early-conceived plants can grow too large before outdoor conditions are safe, leading to transplant shock when you move them into the garden.
As hard as it is to wait, patience is key when sowing seeds, especially for gardeners in cold climates where the last frosts are later.
“If you want to get healthy and strong plants, it’s important to wait for the right planting time by researching the best season for your region,” says Sons.
Tips for starting seeds indoors
Besides waiting for the right time, several other things can help your seeds get off to a good start indoors. Spoonmore offers a few tips and tricks she likes to use on her seedlings before transplanting them outdoors.
First, she recommends watering the seedlings from below after they emerge.
“Bottom watering encourages seedlings to grow deep in their roots because they are naturally attracted to water,” says Spoonmore.
Watering from below will also ensure that you don’t disturb the delicate seedlings after they emerge. You can water the seedlings at the bottom by placing their containers on a tray or saucer and filling them with water. The seedlings will draw water as needed through the drainage holes in the container.
This means you’ll never have to pour water directly onto the soil surrounding the tiny plant, and your plants are less likely to suffer from overwatering.
Always monitor the water levels in the tray or plate. Overwatering is still possible with underwatering, and you don’t want waterlogged soil. If your seedlings aren’t absorbing the water you gave them, it probably means they don’t need water, so you can drain the container and wait a day or two before trying again.
Spoonmore also recommends placing a small fan near your seedlings after they emerge. Introducing a light breeze into the seedling growing environment will help strengthen their stems and prepare them for outdoor conditions. Just be careful not to put the fan too close and risk damaging the delicate stems.