Frost date is early May round here, but I've got a cold frame greenhouse out back and a number of raised beds I've translucent tarps and pipes I can toss over to get them warmer sooner and lets me keep things going longer. Starting seeds in the house is always a bit tricky though, window ledges are prime real estate to my cats and they also tend to gnaw or dig on plants and soil in the house.
have you tried one of those wire kitchen/baker racks? i use a 5-shelf one for my house plants and the cats mostly ignore the ones they can't reach
"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman