“Without hard work, nothing grows but weeds." – Gordon B. Hinkley
If you have a garden, and you don't constantly nurture it, the plants you intend to grow will die, while the weeds take over the garden. If you want to grow the plants you intended, you need to work at your garden: watering, weeding, and maintaining.
I would need more context to be certain, but I believe that the quote you provided is intended as a metaphor. The message is that only through hard work can one succeed. If you sit around doing nothing all day, you will not grow as an individual.