I think you could do that if you choose to write gardening posts that pertain directly to the health & wellness niche.

As Susan suggested below, topics such as organic gardening and recipes would qualify.

I would add: gardening as a form of exercise; gardening as a form of stress relief; maybe raised gardens for people that have problems stooping or bending; therapeutic gardens; types of flowers that you can plant that will help your relax at night - moonlight gardens I think. Things that you could plant in a garden that can be used for aromatherapy purposes. Things that you could incorporate into your garden that will help you avoid hurting yourself, straining your back or tripping, water gardens as a form of relaxation.... Granted, I believe that gardens truly contribute to health and fitness.

So my advise is go for it.... Best wishes.

Personally, I think you should keep them separate, hold all your great ideas so you can come out of the gates swinging when you are ready for your new site. You don't want visitors to get confused when they are there for something else.

Gardening is related to health and wellness when you are gardening herbs and vegetables which are good for your health.
The activity itself is relaxing, in contact with nature, and can contribute to good health I say give it a try and see how it works. Gardening by itself is a big niche.

My opinion, keep in the health and well being theme. If you want branch into gardening, call the new page "Healthy Gardening" or something similar, keeping your original niche in mind. My two cents.😁

There are so many ways to structure a site! I'm so glad you're thinking about it ahead of time. I accidentally didn't think that far ahead and now I have to reorder.

I am trying the hierarchy structure myself. The silo structure works well too though. I am in the make money online niche and I think this works very well for me. The health niche has sooo many possibilities. Remember, Google rewards the more organized sites.

Hi Jacqueline, I think personally that there is so much information to tap into with the gardening and recipes it is almost entirely another niche. It would be worth creating another site. Don't sell yourself short, but do what you can mange.:)
Cass

Health and wellbeing is a very competitive niche. I would definitely still stay in the "niche" within your niche, unless you think your niche is actually about health and gardening? (long shot)
If you feel a passion to write about gardening topics then perhaps your first website is not your final website and the seeds of website #2 (pun intended) could be growing in the back of your mind.

Jacqueline,

I would think that if you want to add a category to the site
you should keep it in line with the health and well-being topic,
that said if the gardening would be organic and the recipes
for your health and well-being, you know like a go together
type of thing then I think that is appropriate and would work :)

Susan
Only my opinion

We agree with Merlynmac. It might be better to wait and add your gardening and recipes to a new site.🥦🍅🥬

You can take that route..my only concern is you may limit another niche you can branch out into that way. You want each site to be about a specific niche...if you do add a garden page that's great but if you think you might branch out into a gardening site, I'd say a separate site might be the best approach....