Sow the spinach seeds thinly in rows spaced about 1 to 1 1/2 ft apart or simply scatter the seeds in blocks. Cover lightly with soil, firm in place and water well. Keep the soil moist until germination. Once the plants have a grown their true leaves, you can begin to thin the plants to about 6" apart. Of course, you can eat what you thinned.
As the weather warms, spinach plants will bolt more quickly. Expect to stop sowing spinach seeds sometime in May or June, depending on your climate. You can extend the season slightly by planting in the shade of taller plants and regularly watering your spinach plants.
Fall Crops: Spinach also grows well in the cool, short days of fall. Start seeding again at the beginning of August. Keep the seedlings shaded and watered and in the summer heat, and they should be ready to harvest beginning in September.
Overwintering Spinach Plants: You can continue sowing spinach seeds late into the fall season. In warmer climates, you could quite possibly be harvesting well into winter. If the ground freezes before the plants mature, mulch them with hay and leave them be until the temperatures warm again in spring. Remove the mulch, and the plants should resume growing, giving you an even earlier harvest.
Growing Spinach in Containers: If space is tight or rabbits are many, you can easily grow spinach in containers. Even a relatively small 10-12" pot or a window box will do. Plant as you would in the garden. However, you will need to water more frequently, since containers dry out faster.