One little seed starting trick I have in my bag of gardening tricks is to start seeds in plastic cup greenhouses! I shared a picture of seed starting in my mini-greenhouses about 2 weeks ago on my Facebook page and I thought today I would share with you the progress of the seedlings. Plastic cups are an easy and effective way to grow virtually any plant from seed. Best of all it’s very inexpensive since all you need is a pair of plastic cups per variety of seed. You can even save cups and wash them to reuse over and over again. Read on to learn more about how seed starting in plastic cups works.
How to Start Seeds In Plastic Cup Mini-Greenhouses
Starting seeds in plastic cups is a very easy way to start some seedlings. Just find two plastic cups (a Solo style plastic cup), one of which must be clear to allow light through. You can choose clear plastic cups or solid plastic cups for the bottom but for the top you need to have clear plastic cups. The plastic cups will cost you less than $3 or could even be free if you collect them after a family gathering or party. If you are re-purposing the cups make sure they are cleaned before you use them. If you are planting seeds in clear plastic cups you may be able to see the root systems for better.
What You Need for Plastic Cup Mini-Greenhouses
- 2 Plastic Cups per Variety of Seeds (At least one must be clear)
- Seeds
- Seed Starting Mix
- Water
- A Little Tape to hold the plastic cups together
Fill the bottom cup with a seed starting mix and water. Put your seeds in the cup and cover the seeds with an appropriate depth of soil then add a little bit more water. Don’t add too much water – we don’t want the seeds to rot. Cover with a clear cup and tape the sides to hold them together.
Once seedlings have sprouted you can take the top plastic cup off. When you do take the top off be sure to monitor the moisture daily. Drying out at this stage is very bad for the seedlings. Likewise don’t add too much water as you can drown the seedlings which is just as bad.
Should you add holes to the cups?
A lot of people ask about putting holes in the bottom of the cups. I have found that I really don’t need drainage holes with this method. I’m very careful about over watering and if I do accidentally put to much water in the cup I just drain it off. I’ve found that my plants grow so quickly that they consume the water very fast making the holes unnecessary. Keep in mind that once these plants are germinated you will need to remove the top which will allow the water to evaporate. The plastic cups are only a temporary location and will get transplanted very soon into the next stage.
If you want to add drainage just poke a few holes in the bottom cup and use an extra cup (a 3rd one) to catch and hold the overflow of water. It may help to add something as a small spacer in between the two cups.
Transplanting
When the seedlings have grown their first set of true leaves you can transplant the plants to individual pots. You can grow a lot of seedlings in a very small space with this method as long as you don’t leave them too long in the cups. If they get too large the roots will intertwine and you may have difficulty in separating them. Remember the plastic cup method is to help with germination not to grow the plants for a long period of time.
The Seedlings Need a Good Light Source
Make sure there is a good light source for your seedlings. It could be a grow light or a very sunny window for the plants to use once they are germinated. Some plants need light to germinate so for them don’t cover them with soil or if you do do so lightly. Your seed package should have the specific seed starting instructions for that plant to follow. Be sure to read those seed starting instructions and help them get a great start!
Why do Plastic Cups work So Well to Germinate Plants?
The plastic cups are essentially terrariums that keep the moisture inside for the seeds to use while germinating. Consistent moisture is absolutely the most critical thing for successfully germinating seeds.
Can you Reuse the Plastic Greenhouse Cups?
You can reuse the plastic cups over and over again to start lots of seeds just make sure you clean them between uses to prevent disease contamination from different batches of seedlings.
Seed starting doesn’t have to use fancy equipment, just think outside of the propagation box! These plastic cup greenhouses are my favorite method of seed starting. What containers have you used for seed starting?
Here’s How I Start My Seeds In Plastic Cup Greenhouses
If you watch the seed starting video you will notice that I am using colored plastic cups for the bottom and only using the clear cups for the lids.
More Posts About Seeds, Seed Starting, and Related Stuff!
How to Grow Ginkgo Trees from Seed
Ginkgo trees are beautiful and amazing trees. These trees (Ginkgo biloba) are native to Asia and can be extremely long lived, as in over 1,000 years! In fact the ginkgo species existed at the same time as the dinosaurs. Ginkgo trees are also called the Maidenhair tree and have fan shaped leaves. In the fall the leaves turn an amazing golden color. In the span…
How Heucheras Begin (Starting Heuchera Seeds)
Recently I started some heuchera seeds while we were suffering through the record setting deep cold of the last several weeks. I had to do something garden related to lighten my spirits that were quickly being squashed by the weather’s entrapments and starting some seeds seemed to be a good choice. It’s easy to start a small container to bring into the house and is…
Seeds and Where to Find Them
By now you may have received your first seed catalog(s) in the mail. It’s a fun time of the year for gardeners. We get to sift through the pages, read the descriptions designed to entice us, and dream of what we will plant next year. When the weather is cold and dreary the catalogs give us something bright and hopeful to look forward to! Which…
Growing Dogwoods (Cornus kousa) from Seed in the Fall
A week ago we found ourselves at the doctors office for one of my children. Nothing major (this time), just a regular check up and physical so she could run cross country (Very cool that a 7 year old wants to run cross country!). After her appointment we left the doctor’s office and found a dogwood tree, Cornus kousa, that was loaded with fruit. To…
How to Grow Heucheras (Coral Bells) from Seed
With all the nasty but necessary weather we’ve been having lately it’s been hard to get out in the garden to work. What’s a gardener to do? Talk about the seedlings growing inside! Today I’m going to give you an update on how I am growing heucheras from seed. The largest of my heuchera seedlings is still tiny but I’m definitely happy with their progress….
Starting Oregon Sugar Pod II Peas from Seed
It’s the seed starting time of the year! This is probably where I have the most fun gardening. I get to imagine the possibilities! This week I started Oregon Sugar Pod II peas by presoaking. It only took a few days after planting until I had germination from the first two seeds. To see how I started the Sugar Pod Peas check out the video…
Discover more from Growing The Home Garden
Subscribe to get the latest posts sent to your email.
Hello Dave! thanks for the idea! I´m making a small greenhouse at home and Iam starting some seedlings,we are finishing our summer here,I hope I can have some vegetables for the winter. besos. Lilián.-
Nice job, Dave! I continue to use my milk jug greenhouses. This year I have jacks-in-the-pulpit seeds "out there!" Hope they grow!!
Hi Dave
That's a nice little tip for germinating seeds.
I grow my tomatoes hydroponically in a polytunnel – in the UK the weather isn't great for outdoor tomatoes – so tend to use the rockwool starter cubes (see http://www.hydro-industries.com/2013/03/hydroponics-diary-germinating-tomato-seeds-in-rockwool/ for details) but I have also been thinking about how to germinate some of our outdoor vegetables using your method – such as runner beans.
I have been using recycled spinach and lettuce containers as well as plastic clamshells that have worked great. I should have used this method before.
Thanks for sharing your success!