Cryptocoryns, except for Crypt. affinis (sometimes still called harteliana), do better if planted in "old" gravel (a year old or six months in a heavily populated tank). Usually slow growing plants, you should see what a CO2 infuser and half way decent light can do for them! (Not mine - darn. Oh wait, not yet.... heh-heh.)

A way around this - somewhat - is to plant your rooted plants in pots or plastic food containers. Fertilizer, laterite and what have you can be placed in there and covered with a layer of fine gravel after the plant is planted.

The draw back is that dead spots can form in the gravel under the pots - especially if an u.g. filter is used. I suppose one could pull the pots up and gravel vac around there. I'd never get that done though. I also feel that pots limit the reproductive spread of some very desirable plants.

A compromise is to place the pots in an otherwise bare bottomed tank. Not quite as attractive, but the tank is easier to clean.