>> What are some easy seeds/vegetables to grown during the fall?
Lettuce, Chard, snap peas, snow peas
These Brassica greens grow fast and will last into cold weather, but might not like starting when it is TOO hot.
Bok Choy, Chinese Cabbage, Komatsuna.
Tatsoi is very cold-hardy
>> Where do I purchase the seeds?
Don't any of the kids' parents save seeds? Not even left-overs from last year?
I like these following online vendors, but local feed stores or farm co-ops will have varieties best suited to your local conditions ... but you might have to buy 5 pound bags!
Some people swear by eBay seed vendors for lowest prices, but I've had bad luck with some eBay vendors.
These first two have very good information about how-to-grow each kind of vegetable. Also, their paper catalogs have great referencer sections about how to grow each vegetable: great details.
http://www.territorialseed.com...
culture guides are listed after each seed packet.
http://www.johnnyseeds.com/c-1...
library of guides:
http://www.johnnyseeds.com/t-G...
http://www.fedcoseeds.com/seed...
http://www.victoryseeds.com/ma...
Hazzards has BIG packets and some good prices, if you already know what you wnat:
http://www.hazzardsgreenhouse....
If you buy from Baker Creek (they have many CLASSY varieties! Especially for melons and watermelons), also look at their "bulk" deals - an ounce of seed may cost only a little more than a few grams:
http://www.rareseeds.com/store...
For Asian greens and other Asian vegetables, I love these next two sites.
Tainong is really a wholesale place for market growers and real farms, but I-Lung also sells sample packets, a scoop that's around 2 grams, for only $2. Shipping is barely over $5. I love that place! They answer the phone in Mandarin, and change to English as needed. And you can always find something to grow that makes visitors ask "WHAT is THAT??!??"
http://www.tainongseeds.com/ve...
Kitazawa is more aimed at small home gardeners, but you can get quotes for pounds or ounces of seed. They have GREAT variety of Asian crops, and detailed descriptions.
http://www.kitazawaseed.com/