Last year I was given one of these
as a Christmas gift.
Which is basically a hydroponic growing system.
If you've never heard of hydroponics, it's basically growing without dirt. The plant is held in place in a variety of ways and it's roots are suspended constantly in water. It's fed by nutrients which are added to the water.
While it is possible to make these systems yourself, this one is nice because it has a little electronic controller
which makes sure that everything is OK. It controls the amount of light that the plants receive (about 16 hrs per day), makes sure that there are enought nutrients in the water, and makes sure that the water level doesn't get too low. All of that for just $100 dollars!!
Seriously, though, I can't say if I had not received it as a gift, I would have invested in one of these or not. Last year, I grew herbs (they were included with the kit) and although the plants absolutely exploded (and I probably could have made more that the cost of the machine by selling the basil alone), I thought that lettuce would be more valuable for us throughout the winter so I ordered that seed pack this year.
Once the seed pods are inserted into the machine and the water and nutrients are added, the machine creates something of a mini-greenhouse effect
so that the seeds germinate faster.
The seed pods say that the seeds will germinate in 1-7 days
and WOW!!! they did they ever!
After just 24 hours...
...the seedlings have indeed sprouted! Can't get that growing in dirt.