Thursday, October 15, 2009

How to overwinter your herbs

I couldn't bear to leave my fresh herbs outside to die in our horribly cold Iowa winter.  I'm in zone 4a, and I can't expect anything to make it through alive if it's outside.  But I'm hoping I'll be able to do something about the strawberries...still working that out though.

So first I dug the herbs out of the hanging boxes

Then I replanted them in individual pots.  That way I can better monitor their water needs and cater to their preferences.

The stevia and lemon verbena were already in individual pots.  Neither of them would have a snowball's chance in hell of surviving an Iowa winter.  But, I successfully overwintered that lemon verbena last year. It lost all it's leaves, though, so I guess it's deciduous.  But it's twice as big now!  Hopefully after I harvest the stevia it will grow back in the spring.

The rest get their own pots.  They're sitting in the southwest window of the bedroom.  It's the best light in the whole place, especially when the southeast window curtains are also open.

  • They need at least 5 hours of sun/day.
  • If you don't have a south-facing window, you can use a florescent light for 10-12 hours/day.
  • Use well-draining soil and let them dry out a bit between watering.  This will keeps the roots happy AND help control those annoying little flies.
  • Keep them cool.  They like the temperature in the 60s.
  • Reverse hardening off — like when you put seedlings outside in the spring, your herbs need to get used to your indoor conditions gradually.  Start by bringing them inside at night, and leaving them out in the sun during the day.
  • Wash them — I just threw mine in the shower for a few minutes. This'll get off any stray potting soil, loose leaves, and bugs. If you've had bug problems, you might want to wash them with soap.
  • Prune them — Experts advise that you cut off 1/2 to 1/3 of the plant.  I did that to the mints (they weren't looking too good).  But everything else is super lush so they just got a trim.  BUT don't harvest any more until you see new growth.  And be warned, that may not happen until early spring.
  • Fertilize in early spring when new growth starts.

If you want herbs to harvest during the winter:
  • You'll need to fertilize them monthly
  • You'll need to give them extra light
  • Don't expect them to survive until next year.  It's tough work producing all year long, and they might just wear out! You may have to start over with fresh plants in the spring.


  1. Nice post, Erin. I'll keep that in mind for my next herb season.
    My mint herb died a week back, and I couldn't revive it :(

  2. Thought provoking post.I found this website useful for Herb Gardening tips I think you guys will find it interesting too.

    Karim - Herb garden plants