Asparagus is generally purchased as a 1-year-old crown and grown outdoors. However, you can start asparagus from seed indoors if desired. You can also choose to keep your asparagus indoors as well. Asparagus is usually not mature enough to be harvested until the spring in its fourth year.
Choose small containers (about 3-6 inches in diameter) to plant asparagus seeds. Transplant them to larger pots if you plan to keep them indoors. You can also transplant your asparagus outdoors, if desired. If you are not growing from seeds, proceed to step 5.
Use potting soil that has a pH between 6.5 and 7.5. Add some lime to raise the pH or sulfur to lower it if necessary. Follow dosing instructions based on your current soil conditions and volume.
Refrigerate and soak the seeds if necessary. Follow the package instructions that came with your seeds. Most of the time you must prepare and soften the seeds. You may need to first refrigerate them for a day and then allow them to soak for a day in water. There are different varieties of asparagus and seeds come in different stages, so again, follow package instructions.
Plant ready seeds ¼ to ½ inch deep, spacing about an inch apart. Water well and keep the seeds in a sunny area of your home in temperatures that average 77 degrees F. Avoid drafty areas if possible. The seeds will take about 2 weeks to germinate.
Prepare to transplant the asparagus seedlings you grew from seeds--or purchased as plants--into another, larger pot, or outdoors, in the spring. Either way, fertilize the new planting site with a super-phosphate fertilizers that is labeled 0-20-0. Two pounds is needed for 50 feet of planting, so if growing indoors, you will need a fraction of this amount. Adjust according to package instructions.
Dig a trench that is about 5 inches in depth in pots or outdoors. Space the plants 18 inches apart. As the asparagus grows, fill in the trench. Keep them evenly moist, but do not over-water, which will cause root rot.