If you used filter media from your pond then you should get nitrite and nitrate readings right away. You have a fully functioning biological filter already.
Actually I would prefer establishing my colony of nitrifying bacteria first before adding in live plants. Serves as a "backup" should under some circumstances my plants died (blackout, algae bloom....etc). At least I would get a nitrate bloom instead of ammonia spike. Plants don't need ammonia to survive, its just a delicacy to them. Just my 2 cents
If you used filter media from your pond then you should get nitrite and nitrate readings right away. You have a fully functioning biological filter already.
I would play it safe and wait a few more days before adding any stock...
My bad if this has been asked.. but how many gallons are we talking about?
Im not sure that if it's a large tank that ghost shrimp and fry will provide enough bio load for it to begin it's cycle...
I actually had ghost shrimp in my 125g when I started it up.. and I thought for kicks I would add a handful of fish flakes.. so I did! again, including Seachem Stability...
The problem with waiting before adding stock is that all the bacteria that are in the filter now, will die without a food source. So when you add the fish, you suddenly are at the beginning of the cycle again and exposing the fish to ammonia.
Once your ammonia is back to 0, you should be fine ... adding filter substrate from another filter is instantly cycling yes but only for a small bioload at a time. I would add something small (or did you say the ghost shrimp and stuff were in there?) and then add slowly (one by one) over time so that the bacteria can adapt.