What sort of plant should I use for the experiment? I'm testing what plant will grow for the longest time of time...
I'm testing what plant will grow for the longest time of time when watered with a mixture of motor grease and water. I know that the plants will die fundamentally soon, but I'll start watering them with the hose down oil mixture after leaves sprout.
What plant sprouts summarily that I can buy in the bulk (seed packets)?
Answers: Are you attempting to grow different species and compare their responses? Or are you attempting to transfer the concentration of oil and compare concentrations of grease and water beside one species?
Most of the kitchen beans (navy, lima, pinto, etc.) will grow quickly, as will popcorn. All are big seed to handle and nice and cheap.
May I kind one suggestion to you? Use plain sand for planting -- no soil or moss or potting soil mix. Organic material and clay adsorbs grease quite okay, and may confound your experiments.
EDITED TO ADD:
Yes, do plant the seeds within plain sand -- it's the "gold standard" for trialling seed germination. That'll be one smaller number thing you hold to worry around explaining.
I would have to agree beside answer #1. Beans sprout and grow quickly. If you are looking for flowers, I would suggest Sunflowers and probably marigolds