It’s early 2026, and we’re rolling back into planting season! This time of year, our main task involves planting seeds and caring for tiny seedlings until the weather is nice enough to plant them.
In 2025, we had a few bottlenecks in our production system, and finding enough protected space for our seedlings was definitely one of them. Over the summer, we added a new piece of equipment that will hopefully improve our seedling germination and give us more space in the spring: a grow tent germination chamber. We’ll talk about how we set that up!
Old System Bottlenecks
As spring rolls along, we have more and more seedlings that need to be protected from the cold. We generally start something like 10 trays of seedlings every single week. All of those seedlings will spend a minimum of 2-3 weeks in their trays, sometimes as many as 9 weeks!
To manage all those seedlings, we had a shelf equipped with heat mats and a thermostat. It could accommodate 16 trays at a time. 12 of those could receive light from overhead grow lights. We also have a small greenhouse nursery that is unheated and can hold around 60 trays.
This system had several flaws. First, we didn’t have quite enough germination space. For plants like onions and parsley that usually take more than a week to fully germinate, we had to sacrifice space on our germination rack and push back seeding times. Also, because we were using heat mats and a thermostat in an otherwise cool room, we didn’t get even heat. That meant we’d see the outsides of our trays have longer germination and slower growth.
Then there’s the absolute mess of our nursery. The space isn’t heated, and we didn’t have any spare heat mats to put out there. So, any time temperatures were even a bit below freezing, we would have to take all of our seedling trays out of the nursery and back inside for the night, then back out again in the morning. This made for lots and lots of time and effort in March/April.
Naturally, we wanted to improve our setup for the 2026 season. We were inspired by Clay Bottom Farm to buy a small grow tent to give us more germination space, more available heat mats, and more space overall.
The Germination Tent
The grow tent we purchased is fairly simple, meant to be a sort of indoor greenhouse. It has a rigid frame, white interior to maximize light, and several ports to accommodate sensors and airflow.
In order to make the tent function as a germ chamber, we need to maintain a constant warm temperature (70 Fahrenheit for most crops), and high humidity to maintain soil moisture. This seems complicated but it is actually crazy-easy. We simply took an old slow cooker, filled it with water, and plugged it into a thermostat so that it turns on to heat the space. The water evaporates and maintains high humidity at the same time.
We built a small rack out of scrap wood that holds 16 trays, and it would be quite easy to raise that to 20 or even 24.
We’ve yet to give it more than a quick test, but our hope is that this germination chamber results in a more even germination across the tray. One complication is that while we installed a light in the tent, we probably won’t use it much, so we will have to be very diligent to remove the trays before the seedlings start growing and getting leggy in the dark.
This chamber is definitely a big step up for our system, but it also has several add-on benefits!
Additional Benefits To Our System
There’s a bit of a waterfall effect to adding this germination chamber – each step down the line will have added benefits to our seedlings and our time.
We’ll continue to have last year’s germination rack fitted with lights that can hold 12 trays. This will be super beneficial for the really tender crops like tomatoes and peppers that ought to be kept inside as long as we possibly can. It will also help acclimate trays coming out of the germination chamber heat, rather than taking them straight out to a cold nursery.
Because we aren’t germination on that rack, we’ll be able to take those heat mats and put them on top of a foam insulation board in the nursery. We hope this will be a huge time saver, as the heat mats should provide enough warmth to seedlings to keep them from freezing in relatively light freezes. In the spring, most freezes are only a few degrees below freezing, so we think we will save a lot of time not having to shuffle trays in and out each day.
There’s even more benefits to the germination chamber though! We made a vent through the wall to our cold room, so that we can actually cool the space using a small blower to pull cold air from the cold room. In the summer, we’ll use the tent not as a germ chamber, but as a “cool room” for things like squash and tomatoes that prefer temps above the near-freezing of the cold room.
We also used the tent to cure sweet potatoes and squash, which need to be kept at high temperature/humidity for several days to enhance flavor and storage.
This kind of dual-purpose tool is gold to a small farm, and we are excited to see how it works this spring!