Sorry to tell you that a six inch pot is too small even for one basil or rosemary plant. A ten inch pot per plant might be ok. And the rosemary is a shrub with the potential to grow four feet high and wide. They also need to be outdoors if at all possible.

^^ Yes! Floral said exactly what I would have.....she just got to it faster :-)

Note also that you’ve actually got 16 basil plants there - count the stems. Each seed usually produces four plants and if you’re growing in pots then they’re best divided when they’re young and grown in their own space.

'Each seed usually produces four plants.' Not in my experience. A pot with your plants would have had four seeds.

You’re right, sorry; I guess there’s actually four individual seeds inside the pod so when you sow each pod you get four plants.

Thank you so much everyone for your advice. What I've gathered is that I need to separate and replant the individual stems into pots that are a minimum of 10" in diameter. Since I don't have the room nor need for 16 basil plants (whoops) I suppose we'll make some pesto out of the extras. What about the rosemary though? Do I follow all of the same rules (separate the individuals when I repot into 10" planters)?

Unless you are planting a hedge of it, one rosemary plant is sufficient for any culinary usage. As floral said, these get to be good sized shrubs under the proper conditions.

Do you have friends who might like a Rosemary bush?

Are you going to try and grow these indoors? If you are growing in less than ideal conditions (ie indoors) you could do three basils in a ten inch pot. They won't get as big as they do outdoors in optimal conditions. I have to grow them under glass and I tend to put five plants in a three foot planter.

@Floral_uk, I'm sure I could give away the extra rosemary plants (:

I am going to be growing outdoors over the spring and summer. I have a large (around 50 square foot) private roof deck that gets plenty of direct sun exposure. I live in NYC, so it gets too cold to have them outside all year round, but I'd like to have a smaller indoor herb garden going througout the late fall/winter on my kitchen window with southern exposure. In this case I would like to keep them in 6 inch pots because that's really all I have room for. Now that I'm realizing how much space these herbs need to thrive, I'm reconsidering my approach to the summer herb garden. I'm wondering if I should just buy some cheap 20 gallon containers and drill holes in the bottom for drainage so that the herbs have plenty of space.

I wouldn't necessarily eliminate the idea of keeping the rosemary outside all year. Several cultivars - Hill Hardy, Arp and Alcade - are rated to zone 6 (NYC = z7). In a large enough container and tucked out of the winter wind, it should be OK and much happier than it would be inside.

One thought: you said you you have a roof garden, so watch out for the weigh since large plants containers with soil can get very heavy. I can hardly move my one BIG rosemary plant in an 18" pot.

What gardengal said above is accurate. I have overwintered rosemary "Arp" multiple winters in the NYC Metro area (7A/7B) urban heat island. And this variety IS usually available in better suppliers in the area. Keep in mind, that there are OTHER reasons rosemary may fail other than cold..., improper drainage, consistently tropical humidities, pests. Mine were reaching shrub like sizes until all seemed to succomb to some pests. I let their gardening bed rest for a year after getting rid of the severely infected plants. This year, I am replanting. I tell you this much, outdoors rosemary chances are infinitely better than trying them indoors..., they HATE being inside!