SRD

Plant Growth

3-level Transmutation

This spell channels vitality into plants within a specific area. There are two possible uses for the spell, granting either immediate or long-term benefits.  
If you cast this spell using 1 action, choose a point within range. All normal plants in a 100-foot radius centered on that point become thick and overgrown. A creature moving through the area must spend 4 feet of movement for every 1 foot it moves.  
You can exclude one or more areas of any size within the spell's area from being affected.  
If you cast this spell over 8 hours, you enrich the land. All plants in a half-mile radius centered on a point within range become enriched for 1 year. The plants yield twice the normal amount of food when harvested.