So sorry I am a bit confused by the word cultivating. If you mean when do you cultivate or work the soil, the answer is to loosen up or cultivate the soil before you plant the seeds on the onions. If you mean when to cultivate to remove weeds around the young plants the answer is to dig out the weeds as they appear around the thin, grass-like blades of the new onion sets. Let me know if I am on the right track about your question. Keep growing, Marianne Binetti