Tips

GROW STRONGER TOMATO PLANTS using the DOUBLE CUP METHOD



Do you struggle with weak tomato seedlings? Are you tired of “potting up” or “repotting” your plants? The double cupping method uses repurposed party cups to grow stronger, more well-watered tomato plants.
#growingtomatoes #indoorgardening #repottingandreplanting

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You can easily and quickly plant a lot of 
tomato plants in pretty small containers,  
but you will find yourself spending a 
lot of time potting those plants up to  
avoid overcrowding and leggy spindly plants. 
A good way to avoid this is the use of party  
cups and a good way to keep your plants evenly 
watered is by use of the double cupping method.
 
In this video I will show you how to 
successfully use the double cupping method,  
while avoiding some of the mistakes 
that I made the first time through.
 
Hello this is Stephen from shortseasongarden.com, 
and I offer tips and tricks for gardening in any  
climate, but especially for short seasons 
like here in zone 3 in eastern Canada. So,  
subscribe to my channel, give my video a 
thumbs up and a comment, and check me out on social media
on Instagram or Facebook at shortseasongarden.
While most plants will not do like their stems  
to be buried, tomatoes are one of the rare plants 
that enjoy being planted deeply and will actually  
develop new roots all along the buried stem 
that make the plant sturdier and stronger.
 
Typically, tomato seedlings are started 
either individually in small cells or  
even with several to many plants in the 
same pot. As the plants grow, you repot,  
or “pot up” the plants into larger containers, 
putting the plant deep into the pot and carefully  
adding growing medium around the stem.
While this method works fine, if life  
gets busy and you don’t get the plants potted up 
in time, plants can get leggy and root bound.
 
Also, as the plants get larger, they require 
more water and can dry out too quickly.
 
All of this can be avoided 
using repurposed party cups.
 
And the best way to water is 
using the double cupping method.
 
All right, so we’re going to show you how to use 
the double cupping method for planting tomatoes.  
There’s different ways of planting tomatoes. 
You can plant them in these peat pellets. And  
the problem with the peat pellet, you can 
see that it’s already needing repotted. I’m  
going to have to pot these up in a few days. 
So, instead of using peat pellets this time,  
I’m going to use these cups. And there’s different 
ways to do it. You can just plant in one cup. But  
I’m going to use a double cupping method. So I’m 
going to put my tomato plant in the top cup. I’ve  
got holes drilled in the bottom, and I’m going 
to put water in the bottom cup. So we’ve got six  
kinds of tomatoes we’re planting here today. I’ve 
got Cherokee Purple, some seeds that I’ve bought,  
some Sungold, and I’ve got some Roma and then 
I’ve saved some Mystery Keeper that keep well  
into the winter, some Big Brandy, I’ve got 
some Brandywine, and I’ve got some Black Krim.
 
So, it’s important to have drainage holes. 
You can see the containers that you buy,  
they have pretty good drainage holes in them. 
So, I’ve got a quarter inch bit and I’m going  
to drill through a bunch of my cups at once. 
It’s easier to do them all at once. All right,  
so that made a hole through all of them. 
I’m going to do four holes. There we go,  
we’ve got some drainage holes in the bottom.
Ok, so we’re going to start filling these Solo  
cups with potting soil, about two inches in the 
bottom of each. Actually this isn’t potting soil,  
it’s starter mix, and we’re going 
to fill them each about two inches.
 
So we’ve got about two inches of mixture 
of potting mix, or starter mix, I guess,  
and perlite in the bottom of each container. And 
we’re going to put some … I boiled my water, and the  
reason I did that is because this starter mix has 
been around for a while and I’m afraid of fungus  
gnats, I don’t want fungus gnats in it.
Now the reason this is brown is because  
I was given a free sample of a product call 
Organic Rev, which is supposed to help with root  
development so we’re trying that out as well. 
You put a capful or two per gallon of water.
 
And so what we’re going to do is fill these 
bottom cups that don’t have the holes in them  
with about half a cup of water. And we’re going to 
set the inner cup right inside the outer cup and  
let that water seep up into our soil.—
In hindsight, it would have been better  
to premoisten my planting mix. Although bottom 
watering is the ideal way to water your seedlings,  
it can take a very long time trying to get 
peat that is completely dried out to absorb  
water. I know this from past experience but 
for some reason forgot how hydrophobic peat  
can be. I ended up getting impatient 
and pouring more water over the top.
 
As a result I ended up with way too much water 
and had to pour a bunch back into the pitcher  
as you can see in this sped up video.
It is important to have some space between  
the two party cups to allow for better 
drainage. To accomplish this, we place  
a small stone or pebble in each bottom cup.
So we’ve got our soil all moistened, we’ve got  
our pebbles down in the bottom to allow the water 
to drain. So now we’re adding our tomato seeds.
 
As you can see, a regular humidity dome doesn’t 
work well over the party cups. Shrink wrap,  
however, works just fine.
Now we put the newly seeded  
pots under our grow lights and wait.
So, I’m done here in my basement. I’ve  
got these under the grow lights. There’s one 
thing I did forget to do—I’m going to do right  
now. I wanted to put a bit of vermiculite over 
those tomato seeds, to not only cover them up,  
but to help ward off the dampness which can 
cause damp off. So I’m just going to put a  
light bit of vermiculite over the top of these 
seeds. And again, that helps prevent damp off.
 
When you are buying expensive tomato seeds, you 
are very careful to limit them to one per cup. I  
saved many of my own seeds and I guess I must 
have been worried about germination because I  
got way too many seeds in some of the cups.
It is important once the true leaves appear  
to thin any extra seedlings so 
there is only one in each cup.
 
Now you can see why we only put two inches of 
growing medium in each cup. As the plants grow,  
we simply add potting soil around the stem. There 
is no need to “pot up” or “repot” the seedlings.
 
To water the plants, simply add water to the 
bottom cup and let it seep up into the top cup.  
When the plants are small, be careful not to 
overwater and drown the plant. It is important  
to have small stones or something in the bottom 
cup to create a drainage space for the top cup.  
Some indoor gardeners will leave the plants 
in the cups long term and allow the roots to  
extend down into the bottom cup simulating 
the Kratky method of hydroponic gardening.
 
If we timed our planting right (about 6 to 8 
weeks before the average last frost date), by  
the time the seedlings are outgrowing their cups, 
it is time to set them in their final home in the  
garden, whether it is in a ground bed, a raised 
bed, a straw bale, or a self-watering container.
 
Check out the above link for my 
popular self-wicking tub. I also  
have videos on straw bale gardening, raised 
bed preparation, and in ground beds as well.
 
If you enjoyed this video, please punch the 
like button. Be sure to subscribe to my channel,  
click the notification bell, and 
we’ll see you in the next video.

48 Comments

  1. Thanks for excellent presentation and information. I am in Zone 10a and we grow tomatoes year round. I love this double cup method. 👍🍅👍🍅👍🍅👍🍅

  2. Looks like you've got a winning plan! Inexpensive materials (especially if you can find used cups). Read comments and cinnamon looks like a good bet! Enjoyed your video – best wishes😂❤!!

  3. Good idea, especially for just a few plants, but a larger water reservoir might work even better… Using a bottom container that gives you a larger gap between it and the cup will let you do "wick watering." Put a piece of acrylic yarn, mason string, or a thin strip of microfiber bar mop towel through one of the drainage holes, leaving a "tail" to dangle into the bottom water reservoir container. If you have a lot of tomato seedlings, forget the bottom cup. Get a plastic light grid panel and cut it to fit just inside your 1020 tray, at least an inch up from the bottom. Put wicks into the cups, dangle the wicks into the tray, ,and you have yourself a big water reservoir for your seedlings. Or do the same thing but put capillary mat material on top of the plastic grid (or other surface), with tails at each end of the tray that dangle down into the reservoir. As long as potting mix at the bottom of your planting container comes into contact with the (wet) capillary mat, water will wick up into the container (with no need for an actual wick in every pot).

  4. If you can find the party cups that have faceted sides rather than smooth ones, you can just turn the inner cup slightly to keep it up out of the water instead adding the stones.

  5. I feel like this is the first time he’s ever done this. Common knowledge you’ve got to get that soil wet before you do anything with it even after he put the plastic over it then he added vermiculite afterwards probably a good idea. What are you doing?

  6. @Short Season Garden hello from another short season gardener (zone 5)! I also start Black Beauty Eggplant indoors. Do you think this would be a good method for them?

  7. And let me put all you lazy gardeners onto Root Riot Cubes for harder to start seeds. They can be a little expensive so I don't use them for corn or beans, etc. I just had 100% germination rate in 3 days using Root Riot Cubes & heat pad on 24 Black Beauty 🍆 & 12 San Marzano 🍅 which is incredible. Both have given me about 50% viable seedlings in past years & usually take at least 7-10 days to germinate.

  8. You can use different size fast food plastic cups, i use large and medium McDonald's's cups from ice coffee that stack up nicely together and have plenty of space for air and clay pellet,

    The lids can be used to hold in moisture if you want, straw hole lets some air in,

    The paper cup holder that you get when you order 2 drinks can be used to hold your cups in a neat row,

    Essentially free and upcycles plastic

  9. Please consider stop using peat. It is so environmentally unfriendly and is doing so much damage its unreal. The release of carbon and distruction of habitat. It takes hundreds of years just to lay down a few millimeters. Please consider peat free compost. Peat is a huge carbon store, better left in the ground. 👍

  10. Just stumbled upon your channel. It's not often that you find an actual short season grow youtuber.
    Though not zone 3.. I am 5 – 6a/b depending on which chart you look at.

    I would have never thought to use plastic wrap for humidity cover.
    THANKS from Spokane, WA

  11. 5:09 filling the cup halfway is too much water, it will have the soil in the top cup under the water line and totally sodden rather than just moist. Instead put a piece of wicking material through one of the holes of the top cup and it will draw up what moisture it needs into the soil whilst avoiding too much water rotting the seedlings roots.

  12. I have seen where, if possible, to use a clear or near clear cup as the bottom cup so that you can more easily monitor the water level.

  13. I'm a breeder. It's easier to use a larger insert with a 1020 as the watering tray. I use a 32-cell insert that fits in the 1020. Each cell has a pot that is 2.5" x 2.5" x 3.5" tall. Common now. Check out Bootstrap Farmer. Much less space and easier to maneuver. Tomatoes are hardy once they get true leaves. You can leave them in a small pot till they are taller than 12"…and more. They won't root-bound in a detrimental way. You could literally cut all roots off and plant them in moist soil and they'll root again. That's extreme, but true only to point out that you can fiddle with the roots some at transplant, especially if buried deeply, and they'll bust out with growth. While in the tray, crammed together, they'll send roots down into the 1020 and suck water too. The critical part is having sanitized soil/mix. I microwave my mix until steaming. I use 1/3 peat, 1/3 coco, and 1/3 perlite. Absorbs and maintains moisture easily. Microwaving it kills disease and bugs. After, they get true leaves, use a very weak liquid fertilizer. My recommendation would be to spend a tad for the 1020 setup I mention and reuse year after year. No need to pot up and it's less space.

  14. Can you explain that Organic Rev and the boiled water? I assumed you boiled the water to pour over the old soil, but if you put the Organic Rev in boiling water, you killed all the microbials?

  15. Remember all those red solo cups and seedling flats are plastic which are made from different chemicals. Those chemicals in those cups will leach out into your plants. I hope you don't throw all those cups into the garbage and then it will pollute the ground water.

  16. I like the double-cups, but it is a lot of work keeping them watered. For many cups, I use an aluminum steam tray. If you wrap the steam tray with landscape fabric (double-wrap) and cut x-slots for the cups, then you can fit about 15 cups with holes and keep them all watered. The landscape fabric fights algae. For the double cups, you can also put a straw through a bottom hole (I cut a slot on the straw so it can reduce size to go through the hole) and a 1/4" funnel and squirt water in with a lab-type squeeze bottle. You can also just squirt into the side of the double-cups. A very versatile method! I use the straws and funnels with 6-cell trays, as well.

  17. That bottom cup is not necessary, if you put all the seeded cups in trays for bottom watering. I also plant into a big dixi-cup with 1.5" fertilized starter soil and allow the tomato plants to get as leggy as they please, then a couple weeks before I am ready to plant, I just fill the cup to the top with the fertilized soil. Soon the spindly stem sprouts roots and fills the upper 3/4 of the cup. They transplant into the garden very well and grow quickly.

    If you leave some leggy plants without topping up, they stay "on hold" for several more weeks as reserves, in case you decide to plant more, which I always do, or if a gopher eats some of your earlier plants.
    Sounds like "plant abuse," I know!

  18. I use the "free" gray cardboard egg cartons ! Great seed starters and by the time they get bigger, tear out each cup and plant in ground. Plus side, the cardboard breaks down !

  19. I purshased my red solo cups right after Christmas the prices drop plus I keep the the old ones easy to reused. I start all my fruits; vegetables & flowers in these cups .❤❤❤❤

  20. If you use a square bottom party cup to plant the seedlings and a round bottom party cup it works great! The square will sit just about right in the round. Cut or drill the square bottom for the drainage holes. Have a happy day!😊

  21. Not sure I see the advantage to double cupping vs just setting in a tray??? Also, I like the idea of letting them grow into the cup height but how to you provide artificial light when they are 1/2 way down the cup? More than one way to do things,,,,just wondering what your reasoning is

  22. Im up in southern interior of bc zone 4. Just found your channel and subscribed looking forward to getting more tips from you. Thanks!

  23. I always start by using Crystal soil in a 5 gallon bucket on top of a crystal soil and water or miracle grow instead of water. I add the. Peat Moss. let it sit for 24 hours checking ul times a day to see if you need to add more water as the crystal soil can suck up quite a bit and it takes such a long time for the peat to hydrate if you’re planning on planting a lot do a 5 gallon bucket with the crystal soil and a 5 gallon bucket with the peat.

  24. What a waste of time and materials. People always trying to reinvent the wheel and here is an example. Double cupping is not neccessary. Even repotting is not needed. Fill whatever pot you want to use till outdoor transplant with 2/3 organic potting mix on bottom and 1/3 seed starting mix on top. Water seed starting mix. Put pots in tray, fill tray with water and they absorb. Plant grows and roots down into the potting soil and continues growing without the need of fertilizing or repotting. This is how I do it and It requires zero repotting or filling wasted cups, etc. Keep it simple people.

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