Homemade mini-greenhouse, Simple DIY Project

When preparing for a garden DIY projects, I consider three things:

1. Simplicity – Do I have the time, skills, or tools to complete this project?

2. Cost – Do I have the funds to undertake this activity and is it worth the effort?

3. Reusability – Is there something that I already own that can be repurposed for this endeavor.

I can answer “YES” to all three questions for the homemade mini greenhouse with this simple DIY project.

I have tried to propagate so many types of plants around my yard only to come back in the next few days to see that the cutting is completely dried out (I just refuse to buy plants at $20-$30 a pop when I already have them).

A greenhouse will trap most of the moisture allowing the plant to stay well-watered which is especially important at this early stage of development. This method will work on many types of plants and vegetables

Simple to make

We used 4-gallon water bottles that we purchased at BJ’s, but you can use 5 gallons as well. The water bottles are only about $5.00, and we already have a water cooler, so nothing was wasted. You can find these water bottles at most major retail stores and if you do not have a water cooler Home Depot is now selling a manual pump for about $10.00.

Once the water bottle was empty all we had to do was cut the bottom off using a razor blade. There is a small hole at the top where the bottle is punctured but we leave it so that a little air can get in.


Extend the growing season

We live in Southern New England and the average growing season for most vegetables is between late May to late September. So, on a good year, this gives us a solid 4 months, which is not a lot of time.

The ground starts to thaw out around the beginning of April this method will allow me to start planting around the beginning of May. However, we usually get a good number of frost warnings until about the third week. The temperature will only dip slightly below freezing so these greenhouses will be perfect to protect vegetables like tomatoes, peppers, and eggplants. This will give us a whole extra month for the growing season.

Where to place mini greenhouses?

The best place to put cuttings and your greenhouse are in a warm area, in the shade. If you put them in full sun then you may burn the cuttings, killing the plant. At this stage of development, they only need about 3-4 hours of indirect sunlight. Place them in a northward or eastward direction where you will get the least amount of direct sun.

Vegetables such as tomatoes need a little more sunlight than cuttings. They will grow much faster in a greenhouse from seed. Keeping these two factors in mind, a little more care will be needed.

Because they will be in more sunlight these vegetables will need to be hydrated to keep them from drying out and dying. I like to use a spray bottle with a fine mist and I will spray them in the morning before the sun hits the greenhouse and then once again when the sun goes down. I will check the soil by sticking my finger in and seeing if it comes out dry. If it comes out dry, then I will add a little extra water to the soil.

If you are using this method outside, keep an eye on how long your spot is in the sun. The nice thing about plastic greenhouses is that they are portable so you can move them around and experiment with the best spot.

If you notice that the leaves are drying out, then that is a good indicator that you will need to move the plant or vegetable.

Reusability and Portability

Another advantage of using these mini greenhouses is that they are super easy to move around. Some vegetables just need to be protected from overnight frost such as tomatoes. But once the last frost is over you will not need to cover them.

I can now use the mini greenhouses for peppers. Peppers like warm weather, the ideal temperature is between 55 to 75 degrees. Where I live in Connecticut, the average nighttime temperature does not reach these temperatures until June, so I would wait until mid-June to plant peppers. Now I can start planting peppers mid-May using these greenhouses to cover them at night and on rare occasions during the day.

The last thing that I want to mention about portability is that they stack easily and take little space to store.

Recycle and Re-Use

One of the disadvantages of using a 5-gallon water bottle is that it does not fit on a windowsill. We like to grow herbs in our kitchen for easy access while cooking and so this type of greenhouse will not fit on our windowsill. Instead, we use a small stick and plastic bag to start the growing process for herbs. We fill up a 3-inch pot of soil, put a stick into the center of the pot, and then put a plastic bag over the top. We do not seal it all the way but leave a little of the bag open. This method is great for small spaces like windowsills.

There are so many great ideas out there for DIY mini greenhouses. I have seen some made from CD cases, old windows, and plastic containers. Look around your home before spending money and reuse old stuff lying around

These mini greenhouses meet all three considerations. They are quite simple to make, you only need a 4-5-gallon water jug and a razor knife. The material is cheap, costing about $5. Finally, once you have invested in the water bottles, they can be reused season after season.

As always, let me know what you think about this DIY garden project and I would enjoy hearing your ideas.

1 thought on “Homemade mini-greenhouse, Simple DIY Project”

  1. Shannon says:

    The idea of “reduce and reuse” is something I think all of us as consumers of today should aspire to accomplish.

    There’s no need to add to the piles of trash already accumulated in landfills if you have something laying around your house that could easily be used for a good gardening purpose.

    Thank you for the inspiration, Matthew!

Leave a Reply

Your email address will not be published. Required fields are marked *