Well, my onion order finally arrived last week and while I’m getting a late start on planting my onions, I’m sure I’ll have a good crop. I ordered three different long day varieties, red zeppelin, yellow sweet Spanish and copra. I chose long day onions because Howard County Maryland is on the border line between the intermediate and long day growing areas. Long day onions start bulbing when day lengths reach 14-16 hours.
Knowing the approximate date of there arrival, I had prepare my raised bed with 10-10-10, adding about .2 pounds on nitrogen per 100 square feet of bed. Since my beds are approximately four feet wide and my onion and leek patch is about 30 feet long (120 square feet), I worked about two and a quarter pounds of fertilizer into the bed (.2 divided by .10 times 120 sq. ft. divided by 100 sq. ft.) The supplier of my onion plants recommended using a fertilizer with a higher phosphorus number then nitrogen and potassium (eg. 5-10-5 or 10-20-10), but I chose 10-10-10 because my soil test shows that I have very high levels of phosphorus in my soil.
I started planting the onions as soon as they arrived. Since my raised beds are very high in organic material and drip irrigated, I planted my onions in a grid pattern with onion plants being space about six inches apart or six plants across my four foot wide raised bed.