Spinach is a very easy vegetable to grow and one that is always expensive in the shops. Fresh spinach from your own garden has much more taste than the week old leaves you buy in supermarkets. Growing your own will spoil you for the commercial stuff.
Spinach plants grow like large lettuces. Plant them about 10inches apart, or thin your seeds to this distance. Plant one row at a time because spinach plants do bolt easily in summer. Plant the next row 18in away and three weeks later. This successive sowing will give you fresh spinach leaves for salads or for sautéed spinach all summer long.
You can plant your spinach seeds in seed trays about three weeks before you plan to plant them. One packet of seed will last you all summer if you just plant twenty seeds at a time.
Spinach plants grow quickly and put on a lot of leaf growth, so they need heavy doses of high nitrogen feriliser. Add pelleted chicken manure before planting and every three weeks thereafter and ensure that you keep the soil moist to keep up with the heavy water demands that spinach has.
You can sow spinach for summer use until the end of April. If you sow another series of rows from mid August you will have a series of autumn spinach crops that will keep you going until mid November.
In milder areas you can sow spinach in September or October and over-winter your crop. Protect from frost with mulch or cloches or sow in a polytunnel.
Pick your spinach leaves as you need them because they do not store well. If you have a glut and need to freeze it then blanch a bag of spinach leaves for one minute in a microwave on full power, cool and freeze.