To control crabgrass, apply herbicides now before the seeds begin to grow. Pre-emergent herbicides kill the crabgrass seeds as they germinate. Along with these products, build up the fertility of the lawn by applying compost and fertilizer. The thicker and healthier the lawn, the less likely crabgrass will take hold. As soon as the ground has dried out, get your spinach seeds planted.
Spinach is a cool-weather crop that grows best in early spring.
Amend the soil with compost and plant seeds in rows or broadcast them on top of a raised bed.