The dry start principle is sound in that the plants take root & can be placed in very specific areas without being blown out of the substrate by strong water flow or being pulled out by fish but... the down side is .... big die off of the leaves when you flood the tank.
Normally a dry start would last at least 6 weeks if you want a complete carpet, growth should be quite a bit faster than when the tank is flooded & even though you can expect leaf die off, once the tank is filled with water, recovery is pretty fast if you supply enough gas due to the established roots...
Normally a dry start would last at least 6 weeks if you want a complete carpet, growth should be quite a bit faster than when the tank is flooded & even though you can expect leaf die off, once the tank is filled with water, recovery is pretty fast if you supply enough gas due to the established roots...