Posted 07 January 2016 - 10:35 PM
I also spell the nutrients given or add some oomph of my own. I will often add my urine or blood to the plants with whom I have a deep relationship. Like Gardensmith noted, patience is key. I've had mandrakes take over 12 months to sprout and avocadoes that took 4.
But I think the idea is brilliant! For seed choices, I would certainly pick an herb or plant that has those particular associations. You could also do the same in reverse, for growing enmity, cursing, or hexing. I've grown alrauns for both healing and hexing - taking the root, carving it into the target, letting it rot, chopping it up, feeding it to my familiars, etc.... You could grow a rose and use the thorns of the resultant bush to prick a poppet of your target in a love spell. You can grow rosemary for protection and then feed it to family members. I've grown lavender at the start of, during, or just before Mercury retrograde for its air associations to increase my communication abilities, for instance.
Though Gardnesmith is absolutely correct that the plants have a spirit themselves. I would work with plants you are familiar with to start as you already have a relationship - you may want to be sure that they are willing participants in your working if you're growing herbs magically. There are a whole host of other gardening magic ideas as well with regard to location, companion planting (and I mean spiritual companions, not just necessarily along the lines of permaculture), lunar vs. solar gardens, etc.