Egg Cartons are for Eggs

Egg cartons are an engineering marvel for the transport of eggs.  The original designer of the egg carton probably never foresaw the wide variety of craft and garden projects for which the humble egg carton would be put to use. 

One such garden project, that I decided to try, is to convert an egg carton into a seed starting tray.  At first glance, the egg carton seems to be the perfect container for this purpose.  The carton is divided into 12 perfectly sized seed starting nooks.  An egg carton fits perfectly onto most sunny window sills.  And, the best part, egg cartons are free.  What more could you want?

So, back on January 11th, I decided to experiment with both styrofoam and cardboard egg cartons to start some seeds.  I read about some pros and cons for each type.  The cardboard version seemed to find favor for the fact that it broke down easily, but many people complained that the cardboard got prematurely soggy.  The styrofoam version was popular with some because it was re-usable and didn't get soggy.

The cardboard carton needed little preparation except to cut off the lid and fill the cells with soil.  The styrofoam carton by contrast needed drainage holes.  This can be done easily by punching holes in the foam with a nail.  Even though it was an extra step, it was simple to do. 

I planted lettuce in the background carton, peppers in the middle carton, and basil in the front carton.  The germination rates in the cartons did not seem any different from using an egg carton vs. a plastic tray.  Although, I will say when using a heat mat, these tiny celled cartons heat up very quickly.  I had to put a towel between my heat mat and the carton to lower the temperature.

There are 2 problems that I saw with using the egg cartons.  The first is that the soil in the cartons dry out very quickly.  The cardboard cartons in particularly dried out very quickly.  In order to slow down the process, I placed the cardboard cartons in plastic bags.  The bags helped keep the soil moist, however, the cardboard turned into a wet, steamy, soggy mess.  Now, the cartons are practically falling apart, and I can't wait for my seedlings to get big enough to move to their new home in a 4-inch plastic pot.

I would have to say that egg cartons are best saved for eggs and perhaps those cute little Christmas tree ornaments that you make when you're in Kindergarten.  I don't think I'll be using egg cartons for seed propagation again any time soon.  

Given the choice, I would pick a recycled plastic tray.  A plastic tray, like the one below, holds moisture without falling apart.  Plus, I can recycle the same container again next year and the year after.  You can't say that for the cardboard carton that sits to the right.