Timing and Herbal Magic.

Days of the Week:

Monday: The day of the moon, fertility, and healing.
Candle and Sachet colors: white or silver
Herbs: aloe, eucalyptus, lemon, mallow, myrrh, sandalwood, wintergreen.

Tuesday: The day of Mars, strength, and courage.
Candle and Sachet colors: red or black
Herbs: allspice, pepper, coriander, dragon's blood,garlic, holly, nettle, thistle.

Wednesday: The day of Mercury, communication, study, and travel.
Candle and Sachet colors: orange or purple
Herbs: almond, celery seed, dill, fennel, lavender, parsley.

Thursday: The day of Jupiter, luck, and fortune.
Candle and Sachet colors: green, purple, or royal blue.
Herbs: anise, borage, clove, hyssop, maple, nutmeg, oak, sage.

Friday: The day of Venus, love, and relationships.
Candle and Sachet colors: pink or aqua green
Herbs: catnip, elder, fever few, foxglove, iris, periwinkle, tansy, thyme, valerian, vervain, violet.

Saturday: The day of Saturn and clearing obstacles.
Candle and Sachet colors: black or deep purple
Herbs: comfrey, elm, ivy, morning glory, mullein, pansy, poplar, quince, yew.


Sunday: The Day of the Sun, health, and success.
Candle and Sachet Colors: yellow or gold
Herbs: ash tree, bay leaves, cinnamon, orange peel, St. John's Wort, witch hazel.

Source:
The Witch Book: The Encyclopedia of Witchcraft, Wicca, and
Neo-Paganism. - Written by Raymond Buckland.

" Herb Magic for Beginners: Down-to-Earth Enchantments " ~ Ellen Dugan

So, on Monday it says lemon, well could it be like "lemon basil"?

You would want to look up the individual properties of lemon basil, or place it under basil rather than under lemon. The lemon for Monday is an actual lemon, not a different type of plant that has a lemon scent/taste.

If it doesn't have any day correspondences, you can work with the herb or the Grandparent spirit of it either through trial and error or discussion.