Newbie veg question...
I have a freshly dug veg patch into which I have planted field beens,
as green manure, which I intend to dig in, in 2 or 3 months, to fix
nitrogen to the soil, ready for next year's vegetable planting.

I have a selection of vegetable seeds here (listed below) all of which
are supposed to be sown after January, according to the instructions.

Can I sow any of them now, with a view to having something edible as
early as possible? I have the use of a greenhouse with a heater so
I'm wondering if it would be beneficial to plant some of the veg in
small pots or something, so that they can be planted out when winter
has passed. I don't have much vacant space in the greenhouse; there is
room for only about 30 plants. These are the seeds I have:

Sweet Peppers
Beetroot
Mustard cress
Tomatos
Cucumbers
Radishes
Lettuce
Chili peppers
Spring onion
Cabbages
Sweetcorn
Broccili
Leeks
Onion
Courgettes
Carrots
Spinach
Parsnip Sprouts
Sweet Peppers
Beetroot
Mustard cress
Tomatos
Cucumbers
Radishes
Lettuce
Chili peppers
Spring onion
Cabbages
Sweetcorn
Broccili
Leeks
Onion
Courgettes
Carrots
Spinach
Parsnip Sprouts

TIA for any advice.

Regards,

JD