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This mini greenhouse is made with just two plastic cups, easily purchased at the dollar store. And it’s a great way to show kids how seeds grow at home or at school! All you need is a few cups, soil, seeds, and tape!

Mini greenhouse with plastic cups

I’m always trying to come up with new ways to get kids involved in gardening, and this mini greenhouse made from plastic cups does just that. The clear plastic cups provide a way to watch the growth of the seed inside, and they keep the heat and moisture in, acting like a greenhouse.

Not only is this a great activity to see how seeds grow, but it can also be an easy way to start seeds indoors without a full tray and seed starting set up. This plastic cup mini greenhouse would be perfect for any gardener just wanting to start a few seeds indoors. Here’s what you’ll need to create these little planters.

And before the supply list, if you want to make a larger greenhouse or coldframe to sit on top of a raised garden bed, check out my DIY Coldframe tutorial made from old windows.

Mini greenhouse supplies

8 oz plastic cups (wide mouth)

seed starting soil

seeds

water

tape

paper for label

How to make a mini greenhouse

1. Gather supplies together. On a small piece of paper, write a label for whatever type of seeds you’re growing. Use a piece of tape to adhere label to one of the cups.

2. Fill the labeled cup 3/4 way up with seed starting mix. Make a half inch hole in the middle of the soil.

3. Place seeds inside the hole and cover with more soil, just below the edge of the cup.

4. Water soil thoroughly, but not so much that water pools at the bottom of the cup.

5. Place second cup on top of the first and use a small piece of tape to connect the top cup to the bottom one (like a hinge).

6. Place cup in a sunny spot and wait. Within a week you should see your seed sprouting and growing. Because of the moist growing conditions in the greenhouse, you shouldn’t need to water unless the soil feels dry to the touch.

7. Once the plant has grown to the touch the top of the second cup, remove it and use it for another greenhouse.

That’s it! Let your plant keep growing in the cup or harden off your plant and move it outside to the garden.

What seeds to start indoors

When it comes to starting seeds indoors, I tend to go for those that I really want in my garden this year and are difficult to find at my local plant sale. This includes:

• Heirloom tomatoes
• Ground cherries (so hard to find!)
• White eggplant
• Carolina wonder peppers

So if there’s a hard-to-find plant you really want to grow, then these mini greenhouses made from plastic cups will be perfect for starting a small amount of seeds indoors. You could also use plastic take-out containers with clear lids. Reuse what you have!

I’d love to know if you’ve made DIY mini greenhouses at home and what you’ve used for them. Comment below and let me know!