Can you start seeds in sand?

While I'm waiting to gather all of the stuff for my aeroponics unit and fixing the roof on my greenhouse, I wanted to know if I can start my seeds in styrofoam cups putting gravel on the bottom then sand? Do you think that should work for most seeds?

Thanks,
Megin

Sand and gravel really aren't going to hold any water so I wouldn't think it would work very well, the seeds need to have more consistent moisture to germinate than what they'll get if they're wet for 2 seconds while you're watering, then they dry out, etc.

The ideal seed-starting medium holds some moisture but is well aerated, is sterile (free of disease and weeds), and does not form a crust-like top. The common term for this medium is "Soilless Mix" and it is usually a combination of perlite, vermiculite, and/or peat.

Megin,

You can start seeds in sand, but it isn't a good idea for most folks. Gravel and sand are commonly used as substrates for hydroponic gardening. During World War II we had a large hydroponic operation on a Pacific island using essentially that approach.

The big disadvantage to sand and gravel, besides more frequent watering and the need to use soluble nutrients very early on, is the weight of the medium. Right now I have an 8-inch pot with a Rosemary in sand that we wintered over under fluorescent lights. (Fresh Rosemary is much more flavorful than dried Rosemary.) I have watered it with a dilute solution of water soluble nutrients, including some calcium nitrate, and it has done very well.

That type of culture is a variant of hydroponics. In fact, anytime you have to start using calcium nitrate as a nutrient, you are basically doing soilless gardening and a form of hydroponics.

That 8-inch pot full of sand is very heavy, wet or dry, and it is really inconvenient to move around. A whole bunch of pots, even little ones, would be inconvenient for that reason alone.

The classic sterile soilless growing medium is some combination of peat moss, vermiculite, and Perlite with a little added calcium and a small amount of nutrients, enough to get the seedlings started. It weighs very little, and you can easily tell if a plastic pot needs watering by just hefting it. If it is nearly dry, it will be feather light, even before the plant starts to wilt. By contrast, sand, with or without gravel, is very heavy, wet or dry.

MM

I start a lot of bulb seeds in 50% sand and 50% germinating mix. Works really well for a lot of bulb seeds.

My daughter's science experiment is in the picture below. She is testing germinating Pea seeds in a variety of mediums. Left to right she is using peat moss, pea gravel, MG potting mix, Sand, Georgia Clay and Water. It's somewhat hard to tell from the picture but the plants in the sand are the tallest and most vigorous followed closely by the MG potting mix.

The key is though she waters each plant a consistent amount (she uses a plastic measuring syringe) every day. So sand works good as long as you keep watering.

BTW notice that the only unsuccessful germination was the clay she dug from the back yard. It has weeds sprouted but no peas. The water germinated them but then they rotted and died.

Jeff

This message was edited Apr 28, 2007 6:54 PM

Thanks everyone!

Thanks for sharing that Jeff, it was really interesting!

there ya go from jkehl daughter's experiment you could probably just use good old Georgia clay. Just put in the seeds and don't water.(at least not very often) sounds like the perfect medium for this lazy gardener.