There are two scenarios for indoor herb gardening.
- The first is you want to bring some herbs indoors from your garden to grow over the winter.
- The second is you want to have an indoor herb garden year round.
So let’s look at both of those scenarios
How To Bring Annual Herbs Indoors
Annual herbs can be dug up, potted into a large flower pot, and moved indoors to extend the season.
The deal is that you’re going to require light to grow herbs inside.
Without grow lights, no amount of winter sunshine (south exposure or not) is going to grow a great herb plant.
They require full hot sunshine to grow properly. Use your grow lights and keep the bulbs 8-12 inches from the top of the foliage for best results.
Sow annual herbs every 6-8 weeks (like basil) to keep a new young and leafy crop coming along.
As long as you give them full sunlight and adequate heat, annual herbs will be fine.
Growing on a Windowsill
I know somebody is going to ask if they can grow them on a windowsill. The answer is “yes” but it’s a qualified yes. There simply isn’t enough light to keep an herb short, bushy and growing well. They’ll get tall, leggy with soft leaves.
So yes, you can keep an annual herb “alive” indoors on a windowsill but it won’t grow well or taste particularly nice when compared to outdoor grown herbs under full sunlight.
Indoor Herb Gardening With Perennial Herbs
Indoor herb gardening with perennials is tricky stuff because most perennial herbs want or need a dormancy period of 8-12 weeks – a resting period – so they’ll start growing again.
What most often happens is that you bring the herb indoors and it simply fades away over a few months and then dies before you can put it back outdoors. They want the colder outdoor temperatures and rest – and they’re not going to produce leaves in this condition.
My advice. Forget about trying to grow perennial herbs indoors over the winter.
Grow them, dry and use them in traditional ways.
Having Said That: Here’s One Way You Can Succeed With Growing Perennial Herbs Over The Winter
If you have a cold cellar, then you can bring the herb container indoors and let it go dormant in the cold cellar for 8-12 weeks. Then bring it out into full sunlight and it will start growing.
The plants will be leggy (not enough light for them) but you’ll get a small harvest.
Before Putting Perennial Herbs Back Outdoors
If you do this, ensure you harden off your plants in the early spring because frosts will damage a soft perennial plant. (Hardening off means putting it outside for a short time on day one – and then adding an hour or two a day until it’s out all day. Then leaving it outside.)
Cut them back before putting back outside (use those cuttings in the kitchen) as they’ll regrow and be better plants (shorter and bushier) with the natural sunlight.
A Simple System To Grow Biennial Herbs Such As Parsley Indoors
Some biennials such as parsley will be fine when brought into the house. Carefully dig up a parsley plant, pot it into a pot that will hold the full root ball (likely a rather large pot) and put it on a sunny windowsill.
The parsley will live most of the winter (yes, it gets leggy and ugly) but with judicious pruning, you’ll have fresh parsley for an extended time.
In the spring, toss the plant and start again with a new seedling.