Another though that just this second came to mind which might be ideal. is to give them a big water flush. I did this before i began nute feeding my current BM twins, an they were still soaking up the flush water nearly 5 days after i flushed them both.
if your not fimilar with flushing , its the process many growers do 2 weeks before chopping there babys. you basically give them double of treble the amount fo water they usually get, and dont stop watering until waters pouring out of the bottom of the pots. its done to ensure all the nutes are fully washed out fo the root system an soil so the plant absorbes only pure water when it come to harvesting time.