I suggest that you take each individual plant species that you are interested in and do some 'google-ing', keeping notes on each one. Use a couple of resources for each plant. Make notations of the expected mature size (width and height) and that information will give you a better idea of how to place/space them in your garden.

It's worth mentioning that just about every novice in garden design UNDER estimates the amount of space needed for their plants. We want to see a finished product from the very beginning, and aren't willing to take into account that the plant may triple...quadruple...or more...in size.

To add to online sources, visit your local library. Without a doubt, they will have one or more books on growing herbs. The books will have easy to reference information on the growing requirements and what to expect from common herb garden plants such as these.

FataMorgana

Thanks.

My new raised bed is constructed, and I will have exact measurements later today, but it is on the small side.

I did the research, and took your advice not to underestimate the future growth potential of the perennial herbs. Thus, I will plant laurel bay, rosemary, and lavendar herbs elsewhere in the backyard with no concerns for space. I will leave my raised bed for smaller herbs.

I have a few specific questions.

1. Oregano
I read that oregano is invasive. Would you recommend planting oregano in a pot? If so, what size of pot will accommodate future growth? Would I have to plant it initially in a small pot, but transfer to a bigger one later? Should I buy one seedling package of oregano (I think there are 4 little plants per seedling package) or more for an occassional culinary use by a family of 4?

2. Thyme should be spaced 18 to 24 inches apart. No issues there from what I understand. Should I plant just one package of seedlings? Again, I will be cooking with thyme on average twice a week.

3. Sage. Based on my research, I should provide 24-36 inches for my sage plant. I don't want to underestimate the future growth. Is this space requirement enough? Should I plant just one package of seedlings?

4. Fennel. I am not familiar with this herb. Should fennel seedling be planted with 9-12 inches of space in anticipation of all future growth? Should I plant just one fennel seedling package? I have never seen one.

Based on my research, no issues with dill, cilantro, parsley, and basil - not much room needed as they are annuals, and I will follow the instructions they are sold with.

Once I figure out the spacing requirements for the perennial herbs, I think I will be ready to plant tomorrow. The weather is in the 60s here in Northern CA.

Fennel will grow about a foot across and 4 to 5 feet high. It looks a lot like dill It will also self seed. The bronze coloured one is especially pretty. The flavour is the same. Fennel has a long tap root and even tiny seedlings are hard to transplant. A pot grown one might be easier.

You could plant four sage or thyme plants fairly close and they will grow into each other to form what looks like one large plant.

Personally I would not consider oregano 'invasive' It spreads and it self seeds but both are manageable. But some people are more neatness/control orientated then me.

BTW parsley is not an annual, it's a biennial. If you leave it over winter it will flower the following year and may self sow.

As well as space requirements you also need to take into consideration the different cultural needs of the herbs. For example sage, thyme, rosemary and lavender need good drainage and lean soil. Parsley and cilantro need more moisture and richer soil. Basil needs full sun. Parsley can take a little shade. Check each of your herbs individually to decide where best to place them.