Kelp placed by player always has age value of 0

So while other crops have age values preset to 0 when planted kelp apparently is random, this makes making auto farms very difficult and even if it harvests once you still have to pray the kelp will harvest twice because it gets re-randomized.

so for consistancy with other crops player placed kelp always has an age value of 0. and also the kelp can grow in a tube that is blocked off from the surface so underground base users can have kelp farms.