When to start oriental squash such as Kabocha?

I have seeds for Japanese Kabocha, the hybrid baby ones. When should I start the seeds and how much room will they need? Thanks.

Hmmm....Must be the holiday weekend.

Your climate is so different that is hard to say. My winter squash are planted as I need to get them going before the summer heat reaches its peak. I also don't know which variety you you are growing, but most will run 8-10 feet or more. I grow some Thai cultivars that exceed 20 feet. Kabochas are buttercup types ( C. maxima) and the only one I have grown is the antique Buttercup. It goes in the 8- 10 foot range, very domestic for a vining winter squash.

THANK YOU, Farmerdill.

I'm not sure of the variety either. It's the one in the picture. I got the seeds from Evergreen Seeds and the package just says Oriental Squash, Baby Delica Hybrid.
However, I just bought some Burgess Buttercup seeds from Ferry-Morse and the picture on the seed package looks similar to the Kabocha. I'm thinking that they can't be all that different. Package says that I can sow the Buttercup as late as June so I'm going to start both now.

I am curious as to why they need to be sown over a hill 9-12 inches tall and 2 feet across?

Tradition: we always did that way. Actually this hill effect prevents the soil from compacting and being hard. Important in heavy soils. I have sand so I use at most 4 inch elevation. It also helps the soil warm up faster, important to those with short seasons asmost winter squash take three to four months to mature. I have not grown Baby Delica, but it is listed as an early maturing variety (less than 90 days). Kitazawa also states that it is a short vine compact plant. ["The short vines of the Baby Delica make it popular with commercial and small-scale growers alike, as each plant produces more fruit per square foot or per acre than other types of squash. "]

As Tevye in Fiddler on the Roof sings.....TRADITION!!!.....

Good to know that there's reason behind the tradition. I have a raised-bed so I won't be hilling it up.
Early-maturing AND short-vine compact plant? That is good news, indeed.

I really appreciate your knowledge and willingness to share that knowledge, Farmerdill.

I love that type of squash. i buy them all the time at the oriental grocery store. I planted them one time but they took over my limited space so I ended up getting rid of it. Our lot is so small that i can not plant anything that need a trellis to climb. Do you eat the flowers? Belle

It is my favorite squash. Most of the time I cook it like I cook a yam. I've never had Kabocha blossoms but have had zucchini blossoms. I have 2 rented plots from the city. They're about 15 ft x 15 ft each. This is my first year with the plots so there are still a lot of bare spots that need to be filled in.