There are two main types of annual spinach: round or summer spinach and the prickly or winter spinach.
Spinach requires a rich fertile soil that has been well worked so that it is fine and crumbly yet one that retains moisture. The plants go to seed quickly on poor soil whilst sandy soil does not hold the moisture long enough to maintain the best growing conditions for spinach.
It is a quick-growing crop so it can be inter-cropped with peas and beans or grown as a catch crop before planting out brassicas or leeks. When forking over the ground, dig in manure and compost to the rate of a bucketful to the sq.yd.
After treading the ground to firm it and break down any lumps, apply fish manure at 4 oz. (120g) to the square yd., rake lightly over then add some bone meal and sulphate of potash as a dressing.
Sowing: Summer Spinach
Sow summer spinach in March. It is better to sow three Successional sowings at 2 weekly intervals. Make drills 1 in. deep and 1 ft. (30cm) apart and sow the seed thinly. These can be thinned three weeks later to 3 in. (76mm) apart.
Thin again three weeks later so that 6 in. (15cm) is allowed between the plants. Those plants that are removed from this thinning will be just large enough to make a tasty dish when cooked and eaten whole.
It is very important that the crop is grown quickly so that it is tender. Water and hoe the plants regularly and feed with liquid manure. Top-dress the rows with nitrate of soda at the rate of ½ oz. (15g) to the yard.
Sowing: Winter Spinach
Winter spinach can begin to be sown during August, and then make Successional sowings through until the end of September. Sow into a bed that is in a shadier position than those, which are sown in summer.
It is an advantage to first soak the seeds in water the day before you intend to sow. If the soil is heavy and water retentive, then it is better to sow into raised beds to aid drainage. From November, the plants should be covered with cloches to give them protection.
Summer spinach should be picked whilst the leaves are young and tender; winter spinach, should have only the largest leaves removed throughout the winter, those plants that still remain at the end of winter will die.