How to Grow Wheatgrass in a Terrarium

Pour the wheatgrass seeds into a small bowl. Fill the bowl with cool water (between 60 and 70 degrees Fahrenheit) until the water is two to three times higher than the seeds. Mix the seeds carefully with your fingers.

Soak the seeds in the bowl at room temperature for 8 to 12 hours. Eight hours is sufficient, but if you want to soak for a little longer because you decide to do it overnight or while you're at work, that's fine.

Drain the seeds and dispose of the old water. Rinse the seeds in cool water and drain them completely. Place the seeds in a bowl in a room with a temperature around 70 degrees Fahrenheit. Keep the seeds out of direct sunlight.

Rinse the seeds in cool water every eight to 12 hours and keep them stored at room temperature until you see small roots beginning to break out of the seeds. This process quickens the rate the seeds grow once they are in the terrarium.

Wash the inside of your glass or clear plastic terrarium with hot water and antibacterial soap. Rinse well to remove residual soap. The interior must be completely clean to avoid contaminating the grass.

Fill the bottom of the terrarium with potting soil mix that contains vermiculite, a water-absorbent growing medium that does not retain excess moisture. Fill to a depth of at least 2 inches. The more soil you use, the less you will have to water. The amount you use varies by the size of your terrarium.

Moisten the soil mixture so that it is completely damp. Avoid creating puddles on the bottom of your terrarium. Spread a thin layer of wheat grass seed on top of the soil; the seed should not overlap, and there should be about 1/8 inch of space between each seed. You can try to place the seeds so that the small roots face down into the soil, but even if you don't, they will grow that way regardless.

Lightly spritz the top of the seeds with a water sprayer. Place the terrarium in a location where it will receive at least 5 hours of full sunlight daily.

Mist the top of the wheat grass with water once per day, unless the soil is still thoroughly damp. The wheat grass will sprout within days, and you can harvest it once sprouts reach 6 inches tall.