Almost every year I buy clumps of thin pale onion plants to line the rickety-rack brick border in the potager. Sometimes I actually plant them...and sometimes I forget I bought the little buggers and they languish...only to rot and become an unhappy mushy discovery in late spring.
I do love the way they march along the edge...soldierly, vertical and upright alongside the ruffly lettuces and greens. Consequently this year I made a point to get them in the ground almost immediately after I brought them home...before my memory had a chance to misbehave.
I planted 16-18 red onions down each interior edge of the four quadrants in the boxwood hedge...4 inches apart and about an inch deep. I amended the soil with compost beforehand and loosened it up quite a bit to make root penetration easier.
A good soak in the warming soil settled them...just before the high wind and cold front moved in.