DIY Humidity Dome for Seedlings




Introduction: DIY Humidity Dome for Seedlings

About: I'm Nicolaj, a Danish chemistry student interested in DIY and projects involving fabrication.

When sprouting seeds or rooting clones it's a good idea keep them in a place with warm and humid air(~20-25°C / 68-77 °F). This is where a humidity dome comes in. Putting the seeds or clones in a Jiffy pot or a Rockwool cube and then filling bottom with water will create a humid climate perfect for germination and seed growth.

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

Step 7: Done!

Happy growing! here I am starting tomato seeds, pepper, Chinese veggies and sugarsnap peas in plastic cups that can be reused for new seeds after replanting. Holes can be cut with the exacto in the dome for a little ventilation if needed.
Don't forget to vote for your favorite entry in the green contest:

Instructables Green Design Contest

Third Prize in the
Instructables Green Design Contest



    • Creative Misuse Contest

      Creative Misuse Contest
    • Water Contest

      Water Contest
    • Tiny Home Contest

      Tiny Home Contest

    22 Discussions


    2 years ago

    I think something is dead wrong with this method.

    As an aquarist, we do emerse grow method (as known as "Dry Start") and use our tanks for that purpose, sealing the top with cling film (stretch wrap) BUT with a very important modification: After sealing the top completely, we tear a little bit from the rims of the tank just to allow the plants to get Co2 from the air as the Co2 is one of the most important variable on plant grow because it is required for photosynthesis process. You need to provide enough Co2 for your plants but sealing the tupperwares like that will cause Co2 to drop ciritical levels or even completely finish.

    I would suggest to drill some holes on the top of the upper tupperware so the plants would always have fresh air (both O2 and Co2). Ofcourse this will cause the humidity to drop on the other hand but it can be by-passed by moistering with a spray and/or adding water to the bottom as needed. My guess would be doing so once a day or even once for every 2 days would be enough if the environment temperature is less than ~26C (~79F).

    By the way, I have serious doubts about the transparency of those tupperwares. They don't look like they will transmit the light without emitting/changing any spectrum/temperature. Even our glass tanks (made of extra clear glass instead of regular glass which means much, much more transparent than regular glass) loses some of the light, I can't imagine what would a plastic do - or don't.

    And again, this will also effect your grow rate in bad way, too.

    So, after all, maybe it's not the best idea to use tupperwares to make a DIY humidity dome.

    I would definetely go for plexiglass if I were to build my own humidity dome.

    I going to show this to my mother she has a green thumb.
    Off topic question: what art program did you use to make the instructions?

    I love this! I'm going to make a few this weekend, I think. I had a heated seed starter but the bed is really flimsy plastic; I could easily fit four or so of these tubs on the heated mat and not have nearly as much worry about the plastic going even more brittle.

    For a quicker way to put holes in sturdy or thick plastic, I use an old soldering iron in a well ventilated area. It doesn't take long and it gives even, neat holes that don't have any jagged edges. The little 'rings' of melted plastic will pop off pretty easily, too, when cool. Obviously one needs to be careful with what types of plastic they melt so as to avoid nasty fumes and fire, but it's worked rather well for me thus far.

    1 reply

    Crazy good! What is not to like about duct tape and hot glue? Keep the ibles coming, Please. I have one ible, do not know why it does not show?

    1 reply

    Very nice Instructable! I use a throw away cake carrier as well (among other things) but your idea seems sturdier and better looking.

    Can you clarify why this step is necessary ? Why the botton of the box need to be black ?

    1 reply

    Roots are sensitive to light, so to protect developing roots it is painted black. This is mostly necessary if using rock wool cubes or jiffy pots, but if using grow pots this wouldn't be necessary.

    This is exactly what Im looking for, I live in a condo and can not put a green house on the patio. I can start my seedlings for my potted plants well before planting season and I can make as many or as few as I need.

    Gosh. I just use a leftover cake dome from the grocery store. It has a black bottom and of course the clear lid is more than tall enough to accommodate pots and sprouts. Plus it has channels in the black bottom that hold water, maintaining humidity without oversoaking the pots. Works great!

    I wonder if the plants will burn or die in Tucson, Az where the temperature can get above 100 degrees...

    Cool instructable! May use it for a new run of cactis...

    But one question: With what software did you make those nice pictures?

    2 replies

    Thanks, good luck with the cacti!
    I used Adobe Flash CS4 for the drawings.

    Thanks! They look REALLY good and somehow better than fotos because of the clearness and simplicity.
    Unfortunately i dont have Ad.Flash :(


    5 years ago

    I've done that

    I love this instructable... I've been looking for something like this for my new seedlings I bought from a gardening expo! This is perfect! Thanks so much for sharing! My vote goes to you for the green design contest!
    Kirin :D

    1 reply