With What Do You Fertilize Boysenberries?

Nitrogen

• Replenishment of nitrogen---which is crucial to the growth of foliage---is essential because water leeches it out of the soil. Few plants produce nitrogen and charge the soil with it (such as legumes); most plants draw nitrogen right out of the soil as their primary food, so it's important to replace nitrogen regularly so that boysenberries will grow lush, verdant leaves with which to absorb sunlight necessary for photosynthesis.

Phosphorous

• Phosphorus stimulates root growth. Bramble berries, such as boysenberries, raspberries and blackberries, have extensive shallow root systems from which will spring new stems and eventually entirely new and separate plants. In addition, phosphorous accelerates maturity in boysenberries, encourages flowering and the production of fruits---in this case berries. Water does not leech phosphorous from soil as quickly as it leeches nitrogen, but you must still replenish the soil with phosphorous regularly. Plants love the stuff.

Potassium

• To keep your plants robust and healthy, be sure they get enough potassium. This helps boysenberries endure changes in the weather and makes them more resistant to diseases. Potassium makes the stems of your plants sturdier by shoring up the walls of the plant cells. An insufficient level of potassium in the soil will lead to slow plant growth and make their stems brittle and weak. While potassium remains in the soil better than nitrogen does, water will still pull it out, so you must replace what is lost through leeching as well as through plant absorption.

Trace elements

• Minor elements, such as iron, zinc, molybdenum, copper, magnesium, boron and manganese, also aid in the development and overall health of boysenberries. Most soils lack these elements or contain too little of them, so be sure the fertilizer you choose contains them all.

Balanced fertilizer

• Different plants require different balances of nutrients. Virtually all fertilizers contain nitrogen, phosphorous and potassium in varying quantities. For boysenberries, select a fertilizer with a 5-2-6 balance (meaning 5 percent nitrogen, 2 percent phosphorous and 6 percent potassium). While the nitrogen, phosphorous and potassium account for only 13 percent of the nutrients in this particular mix, the rest consists of a combination of trace elements (be sure they include iron, zinc, molybdenum, copper, magnesium, boron and manganese) and may contain blood meal, bone meal and/or loam. The filler materials help to distribute the nutrients more evenly.