|Small Construction Site|
Built in a Small Construction Site
When first built, you must seed it with 10 grass and then leave it for a period of time. Up to 100 (depending on size) grass will grow, then no more until it is harvested. Harvested grass remains in the greenhouse until it is taken (effectively infinite grass storage if you don't take).
Grass growth is simple - a greenhouse grows 3 grass per teppyminute until 100 grass has grown since the last time it was harvested. This process is completely linear, which means that it takes 20 teppyseconds to grow 1 grass, and 33 teppyminutes and 20 teppyseconds to grow 100 grass.
The greenhouse is also used for Cross-Breeding. Two of the same kind of plant are placed in two splints in the greenhouse with one Nut's Essence. After 15 minutes, a new item will be made from the two you put in, bearing some of the genetics of each of the parents. You can then remove it and use it as you would normally an item of that type. Flax seeds, flower bulbs, and vine cuttings can all be crossbred this way (though only a like item with a like item - vines with vines, flax with flax, etc.)
Mutagenics, a more advanced form of cross breeding, is also utilized at a greenhouse. Again, two of the same kind of plant are placed in the two splints of a greenhouse, and a drop of mutagen (from a mutagenics lab) is applied. In one minute, two child plants are produced; the one named with a lower number is from the left splint, and the one named with the higher number is from the right splint.