Organic, heirloom and non-GMO seed: what the labels mean and where to buy
Organic seed is seed produced on a certified organic farm, from plants grown to organic standards. It is not a different kind of seed from conventional seed, and it does not germinate better or worse by being organic. Choose it when you want the whole chain, seed to harvest, to be organic.
Reading the labels
Organic: grown and handled under a certification scheme (in the US, USDA organic; in the UK, schemes such as the Soil Association). Look for the certifier's mark on the packet.
Heirloom: an open-pollinated variety with a history of being passed down, typically older than a few decades.
Open-pollinated (OP): seed saved from OP plants comes true to type. F1 hybrid: the first generation of a deliberate cross; saved seed will not match the parent. Both can be organic.
Non-GMO: genetically modified seed is not sold for almost any home-garden crop. In practice the label is reassurance rather than a choice, so organic and open-pollinated are the more useful filters.
Reading a packet
Good packets give the variety name, sowing depth, days to germination and maturity, a packed-for year and often a germination rate. Seed is best used in the year it is packed for; older seed still works, often with a lower germination rate. The database gives expected germination times for each crop so you can tell a slow batch from a dead one.
Where to buy
Dedicated organic and open-pollinated seed companies publish growing guides and honest variety descriptions. Established sources:
Seed banks, swaps and catalogues
Community seed banks and seed libraries lend or swap local varieties, which are often well adapted to your climate. Seed Savers Exchange runs a member exchange for heirlooms. Order catalogues early: popular varieties sell out in winter.
To keep your own seed going, see the guides on saving seed at the end of each plant page.
Organic seedlings and soil
Organic growing starts after the packet: peat-free mix, compost for fertility, organic liquid feeds and physical or biological controls rather than synthetic sprays. See the seed-starting guide for the full routine.