No phosphorus fertilizer for lawns
The new law passed by the Washington legislature limiting phosphorus fertilizers will change the content of lawn fertilizers. How will that affect us lawn owners?
Lawn fertilizers contain 3 major nutrient elements: nitrogen, phosphorus and potassium, listed in that order on fertilizer labels. This new law will require all fertilizers for established lawns to eliminate phosphorus. Will that have dire effects on our lawns?
Plants use lots of phosphorus in their growth process. However, most soils in western Washington have adequate quantities of phosphorus. Most lawn soils which have been fertilized regularly have accumulated much more phosphorus than necessary for growth. So eliminating phosphorus will have no impact.
You can still use a fertilizer with phosphorus to establish a new lawn. You can still use fertilizers with phosphorus for your trees, shrubs, flowers and vegetables. Fruiting vegetables like tomatoes need lots of phosphorus. I would recommend continuing to use high phosphorus fertilizers for those plants. Most other plants will do quite well with the amount of phosphorus found naturally in our soil.