How to Use Humidity Domes to Speed Up Seed Germination
If you’ve ever used them, you know that with humidity domes, germination improves. Choose the right dome, and you have seeds in optimal conditions for sprouting. Experienced gardener, Sarah Jay, discusses why domes are so effective and which ones to use.
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I used to struggle with sprouting seeds and wondered why, until I included humidity domes. Germination rates improved immensely when I did. It was so cool to find out the science as to why this happens, and this understanding has markedly improved my seed starting station.
Your germination domes don’t have to be expertly crafted, and there are full-sized trays out there with a dome that fits over the entire tray. You can even make your own germination domes if you don’t want to spring for one this year. Even a makeshift dome is useful!
Here, we discuss why humidity is the key to faster and more efficient germination, so you have the knowledge needed to understand seed germination in more depth. With this info and understanding, you can more effectively use the tools or the humidity dome of your choice.
Before we get into it, know that a humidity dome is a clear plastic lid that fits over seedling trays or universal bottom trays (UBTs). The goal of the dome is to promote higher humidity within its bounds. There’s more that goes along with that contained humidity, too.
Germination Domes & Bottom Trays for Epic Cells
Germination Domes & Bottom Trays for Epic Cells
How Humidity Domes Improve Germination
Seeds require certain conditions to sprout – namely, warmth and moisture. Placing a humidity dome over your seedling trays has multiple benefits in this regard. The dome traps water, maintaining consistent moisture levels throughout the germination process. Domes also maintain ambient temperature and keep the soil moist longer.
These three benefits may seem divergent, but they all work together to regulate and maintain a stable environment conducive to breaking a seed’s coat so it can sprout. After seedlings emerge, this stability feeds into helping seedlings grow before transplant.
Seedlings need moist but not waterlogged conditions. Domes keep things at the right moisture levels, preventing rotted seeds that don’t sprout. The support that humidity domes provide improves germination rates and supports stronger plants overall. Once plants reach a certain level of establishment, they can handle more extreme conditions.
How To Use Domes
When you use humidity domes, germination improves. How to use them varies slightly based on your purposes. To sprout seedlings, fill your seedling trays with seed starting mix, plant them out, water them, and affix your dome over the top, sealing out any gaps. As water evaporates within the dome, use a spray bottle to keep conditions moist.
If you notice any weird growths, locate the source of the growth, remove the dome, and clean it. After fully sanitizing the dome, you can replace it again and continue growing. When seedlings reach the top of the dome, remove it and let them continue to grow domeless. Always sanitize your trays and domes between sessions.
You can also use your humidity domes for stem and leaf propagation, but only for plants that require humidity to set roots. While cuttings could do with a little less moisture than most seeds, many root more easily in humid environments. The same instructions go for stem and leaf propagation: add more water with a spray bottle as it evaporates within the dome.
Dome Types
There are more types of domes out there than we cover here. However, these are what we recommend. You don’t have to drop cash on your humidity dome setup to boost germination, but you may find your seed starting is more successful.
Expertly-Crafted Domes
In the Epic Gardening shop, we carry seed starting kits that include an Epic 4-cell tray and an accompanying humidity dome and bottom tray. Other similar models on the market are expertly crafted to fit together and function as one unit.
This option is generally the easiest to work with, as you don’t have to make adjustments to ensure it’s functional.
Dome Trays
Similar to kits, like those mentioned above, some domes cover the whole UBT. There are kits you can buy that include a heating element in the bottom tray as well. The dome usually includes some kind of perforation or a modular element that can be changed to vent the tray.
Homemade Domes
Like the winter sowing process, you can repurpose materials from your household to create a humidity-rich environment. Start your seeds in repurposed plastic takeout containers with a clear lid. Situate little starter pots inside reused berry containers. Place large baby greens containers over all your starter pots.
Even affixing a plastic bag over the starter pot has the same benefits. What’s important here is ensuring there’s a good seal between your starter pot (if you’re using one) and your makeshift dome. Before you reuse anything, vigorously sterilize it.
Key Takeaways
With humidity domes, germination improves greatly. Get yours ready for seed starting by sterilizing it and then setting it over your seedling trays. You’ll see markedly higher germination that occurs over a shorter period of time. Remember:
- Domes trap moisture and warmth, keeping the soil moist for longer than if they were exposed to ambient air.
- Remove the domes when your seedlings reach the top, and they’ll continue to grow.
- There are different types of domes you can employ in your seed starting station. Some distributors offer fully functional kits that include bottom trays, starter pots, and domes.
- If you don’t want to shell out the cash for a kit, you can create your own dome by repurposing plastic containers or even plastic bags.
