I Need To Buy Some Stock In Red Solo Cups

Well, I’m still an idiot. That old “out of sight, out of mind” is me.

I use plastic cups for seed starting. I usually use Solo, but last year, they were out of Solo. I got Hefty instead. For me, I consider that a big mistake. The Hefty is thinner and more flimsy. The lip is not as strong. The Solo is thicker and more firm. When I pick up a cup with a seedling, the Solo doesn’t collapse. The Hefty collapsed several times, spilling potting soil and seedling. A few choice words, pick everything up, tell myself to never get Hefty again, and go on with my work. 

Last year, I collected my cups and put them on the shelf in the workshop to clean for use this year. Guess what I forgot about. So this spring, I have had to do what I was going to do last fall.

I use the largest cups I can get: usually either 18 ounce or 20 ounce. I use a drill bit, a screwdriver, a knife, or whatever, to put one to three holes in the bottom. The purpose is to get good drainage. This is no beauty contest. It doesn’t have to look great. It just has to work for your new seedlings. Burrs, flaps, whatever, is fine. Just as long as it drains is all that matters. If you tear up a couple of cups before you get the knack, it is no big deal. You’ll get a technique. You’ll make it work.

Once I have holes in the bottom of the cups, I move over to the 15 gallon muck tubs I have. I usually use two muck tubs, for convenience. I fill both muck tubs with potting soil. I now take the cups with holes in the bottom over to the tubs and fill them with potting soil. Note: If the potting soil is dry, I add water and mix by hand until I have a damp (but not wet) potting soil. I fill the cups with the damp potting soil, but leave about 3/8 inch to 1/2 inch space on the top (like in canning). I sit the cups aside. When I have enough cups done (or I run out of space), I stop filling cups (for now). I then take my seeds and plant the cups. Depending on the age of the seed and what it is seed of, I plant what I think is the proper amount of seeds over the top of the potting soil. It is usually at least 2 seeds and may be 6 or 7 seeds. It is my choice and decision to meet the circumstance. It does not necessarily meet what everyone says is the “proper number of seeds per cup”. It is my cup, my seeds, my decision. Then Fiona tears off a strip of Saran Wrap to cover the top of the cup. She pulls it down firm and smooths out the wrinkles. I then put a rubber band over the Saran Wrap and down over the cup to hold the Saran Wrap taunt. This is now a mini greenhouse. I hand the cup to her and she updates the name on the cup (most are reused and already have two or three names on it). 

Solo cups with seedlings and saranwrap covers.

Note: I use two muck tubs so I don’t have to stop and refill a muck tub. When both are empty, I stop and refill both of them. If I don’t use all the soil in the two tubs, I sit them back in the workshop until the next planting session. The potting soil will dry out, but is still good. And it is sitting there ready to use. All I have to do is add water.

Note: From above, we have a bunch of mini greenhouses. We put them in flats on a grow mat. This provides bottom heat (adjustable). Then we TRY to bide our time until the seeds come up. The Saran Wrap makes a nice window to view the seedlings (hopefully they come up). The head space is to give the seedlings room to grow out of the soil. When we see a seedling coming up, we remove the rubber band and Saran Wrap. There may be even more seeds coming up. After a week or so, we cut off all the seedlings (or transplant them) except for the strongest one. 

Solo cups with seedlings hardening off.

Note: What I like about this method is the cup. When you get a plant front the nursery/big box store/whatever, it is in a small “plug” and is root bound. With the cup, I have more time (and potting soil) before the seedling gets root bound. The seedling is healthier and more ready to grow when planted out into the garden because they are not root bound. They don’t have to recover, they just keep growing. No acclimation for them from the cup to the garden.

Draw Back: This method uses up a lot of space compared to a six pack or four pak. But it results in a much better plant. Don’t let the seedlings dry out in the cups!!!

Note: Cups: You can’t have too many! We stack them on top of each other and put them in a box. I have two boxes of cups: one of new cups and one with prior usage cups. The new box has 318 cups (270 still in plastic and 48 loose). Most (if not all) are Hefty. I got all they had last year. My mistake - live and learn. The used cup box was not counted. There are 500 to 700 cups in there. These are the ones I had to wash. Job done now. Should have been done last fall. If a cup splits or gets crushed or something, throw it away. I have plenty of replacements. And the store has more of them. Solo this time! I used Terrior Seeds advice from their Gardening Almanac. I used 9 parts water to one part bleach for cleaning. I then air dry them. 

Burner with washtub of heated water

So, back to me. We have a stand alone propane burner for large Cajun pots. I have a #2 wash tub I put over it. We use this tub for dunking roosters. I bring the water up to 100 degrees F. to 105 degrees F. I put in about 50 cups loosely. I rinse and scrub as necessary. I put them in a muck tub (we have a bunch of these things). I don’t bother rinsing. My hope is that the bleach will kill any bad organism and rinse/dilute as I water the seedlings. I guess I will find out. I’m not expecting any problems. I may even do a rinse later before using them. Anyway, we finished cleaning all the used cups. We used the muck tub to carry them out to the utility trailer. I turned them upside down across the floor of the trailer to let them air dry. 

Spreading cups out to dry. 

Muck tub to carry washed cups

Helpers

 

Supervisor

We use these cups for spring cool weather crops and summer crops and again for fall cool weather crops.

For tomatoes (and anything we can’t get planted before they get root bound), We have 6” x 6” x 8” high pots we got from Greenhouse Megastore. I think they were Belden Seniors. These will hold a tomato for a long time before it gets root bound. We still start the tomatoes in the Solo cups. When the roots are starting to show on the sides fairly heavily, we transplant them to the Seniors. When weather warms up, we pop them out of the Seniors and plant the tomatoes into the garden. It gives them a nice head start. No transplant shock. Expensive on potting soil. We use the good stuff. It is worth it in the long run. Stronger and healthier transplants are the result.

I have potting soil bought last year at the end of the year on closeout. Before long, I am going to have to start filling those cups and putting seeds in them. It is a lot of work, but I am so looking forward to it. Garden dreaming!!! How’s your dreams?

May God give you your dreams.

Ralph and Fiona

PS: Fiona and I were discussing the bleaching of the cups. It is recommended that tap water sit for twenty-four hours to let the chlorine and fluoride gas off. Bleach is a chlorine product. I went and rinsed the cups to get most of the chlorine off of them. That was my mistake. I should have remembered that earlier.

Bio-dome

PPS: I didn't mention the Bio-Domes from Park Seeds. With the cups, the Bio-Domes aren't really necessary. But I DO have them, and I like them. I do still use them. They are just an unnecessary added expense, just nice to work with. They use a plug format. The plugs are an inverted pyramid with a small short hole in the top (base?) of the pyramid. Remember, the tip (point) of the pyramid is down. These plugs drop into a Styrofoam "frame" with holes for the plugs. The styrofoam "frame" plug hole goes all the way through the styrofoam to the water.  The "frame" floats in water. Then you drop a seed or two or three into the hole in the plugs in the "frame" . The styrofoam is floating in the water with the tip of the plug in the water. Therefore, the plugs siphon water up into the plug to moisten the seeds. There is a dome that fits over the tray to hold humidity up. The dome has vent holes to release excess moisture. When the seeds germinate, I remove the dome. The water can have fertilizer added to it for the plants to use. As long as you keep water in the tray, the plugs have water. I put the trays on grow mats for bottom heat. The system I have is an older system. It has two "frames" per tray maximum. There are three sized holes (and corresponding plugs). They are small, medium, and large. I think large is called jumbo. Some such names. The "frames" are the same size. There is just varying size holes. The small holed ones have 60 plugs (120 per tray). The jumbos are 18 plugs (36 per tray). The mediums are somewhere in the middle. I can mix the "frames". I can have one small and one jumbo together in a bio-dome. The jumbos handle larger seeds like pumpkin/squash. Because the plugs are so close together, they will get crowded quickly. I can and have transplanted from the trays to cups. But I can also go from the tray to the Belden Seniors or straight to the garden. Or, to a huge twenty-four inch patio pot. Again, I plant extra seeds, then snip off the weaker seedlings in the plugs.