Again you need to make as many rows next to the mushrooms so that they produce more. Don't worry too much about the rest yet, just try and get plenty of them made.
In the meantime though, if you have rows of apples or carrots that have extra points on them, do collect them.
If you can combine them with the mushroom producing even better.
The whale companion does help with this because he opens the flowers as long as you gather the apples he needs to activate him.
Combinations can help adult mushrooms too as they can get extra value on them.