I have a terrible time growing larkspur from seed. I try to plant early because I know it likes cooler weather. I get very few plants from several packs of seed. I've been mixing the seed with fine sand and broadcasting it over the loose soil and then covering it with about an 1/8" to 1/4" of fine vermiculite. The few plants i get grow very slowly and never become quite as tall as I'm expecting. I plant in very rich beautiful soil. This year I cold-stratified half the seed to see if it would help (I mixed with non-stratified seed so I don't know which seeds germinated best) I sowed the seed about 5 weeks ago and my plants are only about 2-1/2" tall now on May 26th. Would someone please give me some tips. I'm in West Virginia, zone 6B. Thanks for any help.