How to Grow Basil in a Plug Tray
Did you know that you don't need a garden to grow basil at home? You can easily do it on a window sill or balcony. How? Just grow your basil in a plug tray!
I often use a plug tray (also called seedling tray) to grow vegetables at home. The plug tray is especially suitable when I need to get plenty of little plants at once. You can find this great gardening tool in most local garden centers. The trough has 49 individual cells, which means that I can get 49 perfect little seedlings to plant in my beds outside or in pots later.
- fill the cells with soil
- use your finger to push the soil down, you want it to reach the bottom of the plug (important!)
- put the bottom trough upside down so that the little spikes make holes in the soil
- you could also use the spikes on the see-through lid to make holes
- put the seeds in the holes and cover with a little soil
- put the tray with the cells on top of the spikes in the bottom tray, but don't let it get weighed down on them
- water the bottom trough and make sure that there's always enough water in there
- use the lid to turn your plug tray into a miniature greenhouse, if you want to
How does the watering work then? Well, the seedlings in the upper trough get their water from the trough in the bottom. So you don't have to pour water on top of your sensitive new little plants! You need to make sure that the cell is completely filled with soil though, all the way down. Don't use coarse soil since it might get stuck somewhere in the middle.
Grow basil in a plug tray
Basil is actually a perfect choice for the plug tray. And believe it or not, 49 basil plants won't be too many. I promise, you can't get enough of them! Why not use your basil for a big batch of homemade pesto for example?
Follow the instructions above to prepare the plug tray but try to make the holes in the soil a little less deep. After that, you just scatter a few basil leaves in each plug. The seeds are pitch black and quite difficult to spot on top of the soil. So, I usually don't know how many I put in each cell. Probably a cluster of 4-8 seeds.
Basil seeds germinate better when you don't cover them with soil. So that's why I would water the trough from underneath and then add a lid on top. Put the sowing in a warm spot. The seeds will swell and start to look almost purple within a few hours. They germinate a few days after that.
If you want to know more about basil, I recommend that you check out some of my other content about this tasty herb. Here are a few links:
Air it out
The see-trough lid for the plug tray can cover the sowing entirely, or you could turn it 90 degrees to create a little space for fresh air. Try to do that if you keep your sowing in a very warm spot, for example in a window.
It's actually really easy to transplant the seedlings from the trough. You just pull the little handles on the sides out a millimeter or so, while also pushing the upper trough down. The little spikes on the bottom trough will help push the seedlings up when you do this. So, don't worry about having to get the seedlings out from underneath. The seedling plugs should get pushed from the tray easily if you made sure to pack the soil properly before sowing. Just grab the little seedling and pull it out carefully.
If you don't want to transplant them all at once, you can just lift the upper tray upwards again. Then the plants fall back into the cells.
I'm using one basil plug per pot. You can use more than one in a larger pot though. The basil leaves can get discolored in summer. This is usually because of a lack of nutrients.
Is the plug tray durable?
I actually still use the first one I bought for my garden, which was probably in 2011 or 2012. The little handles on the sides are broken on a few of them, but I can still use the plug tray. The plastic seems pretty durable to me!
I find it hard to get good seedlings, how do you do it?
Since the seedling plugs don't contain that much soil, you need to spend some extra time on transplanting and also add fertilizer to keep the seedlings healthy. You need to keep up on the watering and also make sure that they have enough soil to have a growth spurt. Don't leave the plants in the plug tray too long though, they won't thrive in a space that small.
How many seeds in each cell?
I usually sow several seeds in each cell, at least when it comes to basil, onion and a few other vegetables with very small seeds. I only put one per cell if I grow cabbage, lettuce, beets or summer flowers for example.
The roots don't reach all the way down. What should I do?
The roots will grow downwards if there's enough soil in the plug. It's actually surprisingly easy to forget putting it all the way into the cell. If the roots don't grow, then there's probably something going on. Are the seedlings getting everything they need? Water, heat and fertilizer is the ticket!
Basil grows really quickly. I harvest my basil plants by simply cutting them, and I do that right above a pair of leaves. If you do it that way, the basil plants will grow new shoots that you can harvest later. One thing you need to keep in mind is that your basil can bolt quite easily if it's warm and sunny.
I transplanted around half of the plants in my plug tray recently. The temperature is quite nice now so I keep my basil in the polytunnel even during the night. If it were to get colder, then I just take the whole box inside and put it in my bathroom.
You can take your basil plants indoors and keep them on the window sill when it gets colder outside in fall.