SQUASH FAMILY CROSSES, By Nick Guthrie

Members of the Squash (or Cucurbitacaea) family are many and varied – in size, shape, colour, & storability. Most of those grown in this area (unless you are growing exotics) fall into 3 species – Cucurbita ‘maxima’, C. ‘moschata’, and C. ‘pepo’. Those that have outstanding keeping qualities and drier flesh are usually referred to as winter squash, while those that have young, tender skin and fewer seeds we call summer squash. However, all squash and pumpkins can be eaten when young and tender, and also when mature.

When deciding which squash to choose for eating and seed-saving, you need to know which variety you have, as they will cross-pollinate within their own species. For instance, zucchini, – which we all love to hate, and grow masses for our friends, – is a Cucurbita ‘pepo’, which will cross with any of the dozens of other C. ‘pepo’ types like ‘acorn’ or ‘vegetable marrow’. The one called ‘buttercup’ will cross with ‘hubbard’ as they are both C. ‘maxima’. ‘Butternut’ – my favourite – is a C. ‘moschata’.

So – I suggest – in order to keep your squash breeding true, – that you grow only two kinds per year, and that they must be from two different species. If you live in town, you will need to talk to your neighbours to determine which type they are growing, as the pollen can be carried great distances by insects.

If you intend to keep seeds for replanting and expect them to be true to type, the only way to ensure this is to tape closed, or bag and tie, the flowers you wish to keep – during the flowering period and hand-pollinate them, which is finicky and time consuming. Make sure you can identify male and female flowers.

1. C. ‘maxima’
   • Buttercup
   • Delicious
   • Hubbard
   • Mammoth
   • Kabocha
2. C. ‘moschata’
   • Butternut
   • Crookneck
3. C. ‘pepo’
   • Acorn
   • Delicata
   • Jack-O-Lantern
   • Small Sugar
   • Straightneck
   • Vegetable Marrow
   • Vegetable Spaghetti
   • Zucchini 

Of course, there are many more than are listed here. When you buy a packet from a store, make a note of which of the 3 species it is, in case you wish to keep seeds and give them to your friends. They, and you, will need to know what to expect next year.

[notice]NB It is worth noting that the various “pumpkins” are in all three species![/notice]