Herbal magic, thankfully, uses little to no tools in compare with other types of magic. However there are tools that do come very much in handy when doing herbal magic:
Mortar and pestle set- These are needed if you want to grind your herbs and seeds, like if you wanted to make incense.
A large wooden or ceramic bowl- Try to avoid metal, these are used for when you want to enchant herbs. Also, you can keep a large glass or enamelled pot exclusively for making "potions" or infusions.
Sewing supplies- Keep it simple, supplies like needle, thread, cotton, thimbles, scissors, pins, etc., are very useful in making satchets or poppets which would also reauire multiple colors of cotton, fabric, and yarn.
Candles are also very useful, as well as candle holders, censers (incense burners), charcoal blocks, and jars to store herbs in.
Another useful thing to have is an altar. The altar is just a separate space where all magical work is done. You don't need an altar for everything you do, however certain rites require an altar to be used. Spells can be performed at it, it can be a work table for composing satchets or enchanting herbs, it is a place, in general, where all magical work is done.
You don't need a separate and elaborate space for your altar if you don't have room or can't acquire one for whatever reason. Your altar can be the coffee table, dresser, or even just a small section of floor. Whatever works for you.
If you wanted as well you could also wear robes and jewelry specifically meant for performing magical rituals. In fact, some practitioners prefer not to wear anything at all while performing magic. It is all in preference, there is no one way to do something and if one way works for you than go for it.
This information can be found in Scott Cunningham's Encyclopedia of Magical Herbs.