Summer projects, though of course not strictly necessary, are nonetheless a welcome diversion, particularly if you have children to entertain, and sowing squash is a failsafe exercise that will yield fantastical results fast.
First: some word-play for anyone who is confused.
All pumpkins are squash, but not all squash are pumpkins.
Squashes are all species of the genus Cucurbita, and are generally divided into two groups:
Summer squash (courgettes and marrows are summer squash) are harvested in summer
Winter squash (butternut squash and pumpkins) are harvested at the end of summer, hence the harder skin and the flesh that needs cooking.
Gourds are very decorative squash, generally deemed inedible but definitely worth growing for their ornamental value.
All pumpkins and squash are also very useful for suppressing weeds if you have a bare space to fill.
First, find some seeds; This year I am growing Tromboncino and Uchiki Kuri - tromboncino is a climbing variety with weird and wonderful long fruits that you can eat raw, at courgette stage, or allow to harden, and Uchiki Kuri is a lovely orange-skinned squash with delicious flavour.
If you are reading this in April or May:
Sow seeds singly into small pots 7-10cm diameter (or make your own from newspaper) full of damp, peat-free multi purpose compost. Poke the seed in on its side, using a lolly stick to make a hole in the compost first.
Put the pots in a lidded tray somewhere warm, like your kitchen, until you see them start to sprout, at which time you need to remove the lid and grow them on, ready to plant out at the end of May/beginning of June. You can raise seeds indoors like this until mid-June if you like, but it would be optimal it get them going as early as possible in order to have full, gorgeous plants.
If you are reading this in June, July, August:
You can sow them direct, outside.
If you're sowing (or planting out) in the ground, prepare about a square metre of it per plant (refer to individual seed packets for spacing) by removing weeds and digging in some well rotted manure. Poke two seeds into the centre of the patch, pushing them in a couple of inches deep, and protect with a make-shift, open-top cloche cut out from an old plastic bottle. Water well every day and as soon as you see action, cull the weaker seedling and watch the lucky one go.
You can also grow them in large containers like I do, using exactly the same method as above, but I'm a bit meaner with space in a pot, as I'll be paying close attention to feeding regularly and I'm not in it for prize fruit. I'll be putting two, perhaps three tromboncino into a 70cm diameter pot.
If using a container, make it as large as possible, and fill with multi-purpose compost, mixed with some well-rotted manure. Watering is crucial, and start feeding once a fortnight as soon as fruits appear. You can either let your vine gallop along the ground, or up a tipi or over an arch.