Herb gardening is all about timing and cycles. We have a zone 7 garden, and late summer and fall can be a bit of a slump in terms of harvesting.
Generally, herbs harvested for their leaves are best harvested right before blooming. If you have been pinching back the tops on your herbs to delay bloom and encourage the plants to fill out and produce more leaves, some of your herbs may almost be ready for harvest.
For the most part, though, this is a slower time when most of the annual herbs are spent and a few perennial herbs are either coming into a second bloom after a first harvest or just getting ready to bloom for the first time. Most perennial herbs have completed blooming for the year and are already focused on building up their roots for the coming winter.
It’s not quite time to harvest fall roots like echinacea - that comes later for us, sometime in October or November, after the first frost.
Even though there isn't much to harvest, this slower time of year is perfect for cleaning up the garden and getting ready for fall. It can be a good time to plant seeds that require stratification (alternating warm and cool temperatures), try to sneak in a second fall planting of annuals like calendula (and a fall veggie garden, for that matter!), or prep any garden beds that you would like to use for fall-planted perennial roots.
Wondering what to do in your own herb garden this time of year? Here are some of the tasks I like to work on and some of my best tips to help you out!
Stay Ahead of the Weeds.
If you are using organic methods for your garden, this is usually an easier time of year for controlling weeds, but that doesn’t mean you can rest! Most weeds have slowed down because of the heat. If you have been careful to take care of any weeds before they set seed then you shouldn’t be fighting with fresh seeds ready to pop up - but weed seeds can persist in garden soil for years, so it’s an ongoing battle. Use a hoe or a hand tool to gently cultivate around your plants to discourage any weedlings that you notice
Late summer is often the perfect time for collecting seeds from your plants. Deadheading (removing spent blooms) earlier in the year helps your plants stay healthy and may encourage them to re-bloom, but now you can leave the flowers on the plants and allow them to set seed. Although I like to collect some of my seeds and keep them in envelopes until spring, you can also fall sow your fresh seeds or leave the seed heads on the plants all winter for wildlife.
Clean Out Beds
Annual herbs have most likely died back by now if you started them early in the spring. Now is a good time to clean out those beds and add compost or other soil amendments if needed. Adding a little organic matter like leaves, grass clippings, or manure directly into the beds and turning it under, then letting the beds rest until spring is another option. Doing so can help improve soil quality over time, especially if you have heavy clay soil. Just remember that plants may not do well in these beds until spring - the manure and plant matter will need time to decompose before the bed will be ready to plant.
August and September tend to be good months for planting perennial herbs seedlings with strong root systems - especially plants like echinacea, black cohosh, and elecampane where the roots are the main parts utilized by herbalist. The weather is a little less scorching, for one thing, but there is also enough time for the plants to get settled in before going dormant for the winter. In my experience, fall planting allows them to bounce back in the spring and they are healthier than the times I’ve waited to plant them in the spring instead. You can either plant out or transplant seedlings that you started in the spring, or purchase your live roots this time of year without worrying that hot weather will hurt your tender seedlings.
If you have some herbs that you’ve been wanting to split up and move to other areas, fall can be a really wonderful time to do that. Late August and September are my favorite time to divide and move plants around- as long as we have been getting enough rain. During a dry year I will leave things where they are. Having less water than usual can stress plants out, and moving them around on top of that can make them even more unhappy.
Mulching your beds again with leaves or bark is a nice way to tidy them up for fall. Just remember that pine straw is very acidic and oak leaves contain compounds that inhibit the growth of other plants - so these two materials are probably not the best for your herb garden even if you have an abundant supply. Mulch helps retain moisture, adds a layer of insulation for your plants, and helps somewhat with weed suppression. Over time, mulch breaks down and adds organic matter to the soil - making for happy soil and happy plants!
Below you can find a very informal video of me explaining how I’m getting my garden ready for fall and offering a little tour of some of the plants that are currently in my garden. Last year was a very bad year for us because we didn’t have rain for three or four months during the hottest part of the year! Most of last year’s projects didn’t survive. Then, this year, I made the transition from mainly being self employed as a writer to full time employment “in town” as we like to say around here - so you will notice lots of empty garden beds.
If you’re a gardening nerd like me, there’s nothing quite as exciting as an empty garden bed just waiting to be filled. Getting the garden caught up felt really good, and I can’t wait to see where next year’s garden adventures take us.
All the best,