I thought I'd share a gardening/cat owner methodology for allowing you to start plants indoors during the winter months, and let the felines enjoy the garden window too. We found that our two monsters are gardeners. Dirt on the floor, plant starts chewed, the usual "I'm bored! What's this?" Cat routine. So, being a frugal recycler, I tried this and had good success with it. I use yogurt cups, and the large peanut butter, or roasted peanut plastic jars to make minature hot houses for seed starting. Very effective for getting going. But you're definitely limited in plant height. The ones in this picture are calla lilies started from seed.