Trying to finagle a way to make a more considered version of this guide... it seems some of the information I got from the Sims Wiki was... inaccurate? Or at the very least outdated.

Hmmm.

EDIT:

Current analysis suggests that, in the base game, every possible 'special' grafting combination can be held within a minimum space of:

• two 2x2 garden planters, which each hold four small plants or one tree (eight plants)
• three 1x1 garden pots, which each hold one small plant or tree (one plant, two trees)
• total number of squares occupied: 11

With the vertical planters (which are very space efficient, but cannot hold snapdragons, lilies, or orchids) from Eco Lifestyle:

• four 1x1 vertical planters, which each hold two small plants (seven plants + one free slot)
• four 1x1 garden pots (two plants, two trees)
• total number of squares occupied: 8

The wiki claims that Dragon Fruit can't be held in vertical planters, but this seems to be...wrong?

Further notes.

In my original post, I claimed that growth rate influences how often product is generated. This is untrue - it was true in old builds on the game, but in the modern version of the game all plants produce product at 5 am every morning, regardless of growth rate. It may still have some influence on how long a plant takes to mature, though.

In an outdoor garden, with Seasons installed, the optimal grafts (listing the "base" plant first, and the "donating" plant second) for max production days are:

• Snapdragon (Spring/Fall) + Strawberry (Spring) = Dragon Fruit
• Snapdragon (Spring/Fall) + Dragon Fruit (Fall) = Cow Berry
• Snapdragon (Spring/Fall) + Lily (Summer) = Orchid
• Orchid (Spring/Winter) + Pomegranate (Winter) = Death Flower
• Bluebells (Spring/Summer) + Strawberry (Spring) = Grapes
• Rose (Spring/Fall) + Grapes (Fall) = Bonsai Buds
• Sage (All Seasons) + Basil (Summer, Fall) = Parsley
• Chrysanthemum (Summer/Fall) + Tulip (Spring) = Bird of Paradise
• Lemon (All Seasons) + Pear (Fall/Winter) = Plantain

Additional notes:

• For an indoor garden with vertical planters, the first two snapdragon recipes should be reversed.
• Daisies (Spring) and Strawberries (Spring) are basically interchangeable in their grafting recipe.
• Apples (Fall) and Cherries (Summer) are both active for one season each, though Cherries have a slower growth rate.

Finally, the following base game plants are neither components nor products of any splicing "recipes":

• Summer: Tomato, Blackberry
• Fall: UFO Fruit
• Fall/Winter: Onion
• Winter: Spinach, Potato
• Spring/Fall: Carrot, Mushroom
• All Seasons: Trash Fruit, Growfruit, Forbidden Fruit of the Plantsim, Wolfsbane