Gee, I get the hedge-trimmers onto mine! Find a likely-looking spot and CHOP. Your plant is obviously only small, but it doesn't really matter where you chop, as long as you don't remove more than about one-third of the total growth all round. No need for pinpoint accuracy.

You can't generalise with herbs. There are only about 20000 of them. But for shrubby things like basil or rosemary, the same method works well.

If you want seeds, you just leave the flower or flowerhead intact until the seeds have fully riped.

Thanks.

About seeds? How do I know they are ripe to harvest?

Again, it is hard to generalize for all "herbs." But as a general rule, when the seed pod is dry. In plants that make large fruits like squash for example, it could be much different.

While the book is primarily designed for vegetable crops, Seed to Seed by Suzanne Ashworth has much about seed harvesting, saving, and starting in it. Find it in a local library and do some reading if you are interested in seed collecting. Many techniques are applicable to other plants. You can also google seed collecting and the specific herb you are wondering about as well.

FataMorgana

allenwrench, I tried to harvest basil seeds 2 years ago but found that mostly the plants had beaten me to it and had gotten rid of their own seeds... I'm not sure about your zone, but here in Savannah basil self-seeds VIGOROUSLY!!! I have basil in the flower beds, basil in the raised veggie beds, basil in the lawn... You might consider just letting it go to seed at the end of the season and then standing back in the spring...!

If the '6' after allenwrenches name is their zone then possibly basil will behave differently than in Georgia or Australia. In Daisy's climate basil and rosemary are 'shrubby'. In mine rosemary is shrubby but basil is a tender annual which most years I can't even reliably put outdoors because we just don't get enough heat. I sow and grow mine in a pot under glass in order to keep it warm enough and start it new each year. I sow it quite thickly and treat it like cut and come again salad crops. To germinate it outside I would have to wait until about the end of July to sow it and even then it might not germinate. I have tried to overwinter plants indoors but they just sulk and die due to low winter light levels and fluctuating temperatures. Rosemary on the other hand is totally hardy and grows huge, as do baytrees. So allenwrench needs to check his/her local conditions to get the best out of basil.

Thanks for ALL replies!

I've got a rosemary that's hardly done anything all summer. I got two oregano from the nursery and they died off very quickly. I've got a spicy basil grown from seed that is very full but short, and a sweet basil that is fully 2 feet tall and almost as big around. 8a had plenty of 90 degree days here, now lots of water and very cool 48 last night.

Never had a problem with collecting basil seeds, for me they turn brown and are quite dry still on the plants. I just cut the stems and strip off the seed pods. I never bother to remove the pods, just replant the next year. They do well from fresh seeds. Does well even up in Colorado where I use to live. I found if I had a problem with basil just replant. If you save seeds you won't have to worry about the expense and will have plenty of seeds for many years to come. Rosemary is best started from cuttings of woody stems.

Rosemary is best started from cuttings of woody stems.
Interesting, I have some smaller cuttings trying to start right now, but I also have some large cuttings I'll try them as well.

I don't usually cut back my basil, I prefer to plant it in intervals so it is always fresh and young. Leaving one of the better plants to go to seed of course.