Yes but not all of those will apply to gardening, I believe a few other approaches could be taken with gardening channels.
Have you tried any offline advertising? I dont know exactly what you do in your gardening videos but it could be a good thing to network and meet up with local gardeners regularly and share your channel with them, who is your target audience? If you figure that out and its say newcomers to gardening and your channels goal is to help people get into gardening with easy to follow gardening tutorials and tips you can focus your content on that as well as your optimisations.
As Derral mentioned optimising your titles and descriptions would really help, how you do this is on a per video basis, you want to think about how others are going to discover your video. For example if you had a video on planting garlic bulbs indoors and it was a how to kind of video you could have the title as "Planting garlic with Jenny", now that title isnt awful but it doesnt take into account what people could be searching for, for example How to Plant Garlic Bulbs Indoors or How to Grow Garlic Indoors For Beginners. Consider who might be looking for your video and who would find it useful and title it based off of that. You can also research what people are searching using the Google Adwords Keyword Tool/Planner.
For your descriptions make sure to write about the video you have made and place the title within it or at least a portion of for example:
How to Grow Garlic Indoors For Beginners - Jenny the gardener shows you
how to plant garlic bulbs just in time for Summer, following these
indoor gardening tips you will discover the easiest way to have lots of garlic every Winter that you can crush and put in your favourite dishes.
I have bolded some examples of optimisations for searches that could be relevant and highly searched
I hope that helps.
Best of luck! And yeah just follow the advice above! 
