Gardener's Dictionary: NPK
NPK (n.): NPK is the three numbers listed on fertilizer bags and containers that explain the balance of nutrients in that fertilizer. NPK stands for nitrogen (N), phosphorous (P) and potash or potassium (K). Each letter of NPK corresponds to the number on the bag and symbolizes how much of that nutrient the fertilizer contains. Different container plants in the balcony garden need different levels of NPK, so certain plants may require fertilizers with different NPK levels.
