Cover crops for undersowing

Hi there,
Looking for recommendations for cover crops to undersow finish crops to try and have some coverage over winter? Could winter kill or not. I grow cut flowers/culinary herbs so existing stands of plants will be anywhere from 10"-48" tall. Likely would be sown through late July into early September.


Hi Jess,

I’ve had good germination and coverage by surface sowing dwarf white clover. If you’re not able to incorporate the seed then this is probably your best bet, as the seeds are so small they just fall into any crack or crevice and germinate with a good rain or even a few substantial morning dews. Rye will also do well to get established before the snow flies and it keeps growing March/April the following spring.

For winterkill stuff probably oats or annual rye for that sowing window but it helps with these to get them scuffled into the earth so that they’ve got moisture/the birds don’t eat 'em. Getting those germinating in July will give you a nice mat for soil coverage into spring. What are the plants you’ll be undersowing?

some suggestions for info to make cover crop decisions
and your decision should include a review of specific allelopthic relationships between your cover crop and your cash crop.

Thanks Sarah and Eric!

Sarah, definitely early hardy annuals like dianthus, feverfew, sweet peas etc. But generally thinking about if I can get a nice short mat in, that be ideal. I tend to leave things in or mow them late because I’ve got plenty of room and don’t have to fill beds. I’m also on a BCS raised bed system.

Eric, I use Speare’s–they’re great-so much diversity.

Hi Jess,

I’ve been trying this out with the veg too and one book that has really helped me figure out what to use is Growing Green by Tolhurst & Hall. They have easy to read charts that detail what each cover crop does, when it can be sown, etc that has been a great tool.

I’ve tried out dwarf white clover in my kale beds and that overwintered nicely to create a good thick mat the following spring. Also tried out some winter kill cover crops like berseem clover & crimson clover, as well as oats & peas and buckwheat. Any of those would be fine planted in the time period you mentioned (buckwheat should go in earlier I think, early August). I’m aiming to move towards more winter kill cover crops so that it’s easier to deal with, not having to work it in to kill it.

Aside from whether the cover crop will come back in the spring, if you’re under sowing into an existing crop, a good thing to look at is the root structure of your flowers vs the cover crop, to make sure they aren’t competing with each other too much (ie taproot vs shallow spreading roots)

Good luck!


Thanks Martina! This is super helpful and I’ll check out that book!