Over Feeding Your Plants
Your plants do need to eat, and eventually they will use up the nutrients in your soil. But it can be all too easy to feed them too much.
Over feeding your plants can happen whether you use chemical fertilizers or organic fertilizers. If you are using minimal fertilizer the plants will take it in relatively quickly. Excess nutrients (we are generally concerned most about nitrogen, phosphorous and salts) are flushed into our ground water, streams and lakes in heavy rains. And eventually, especially without heavy rains, soluble salts will build up in the soil. This can cause what gardeners commonly refer to as "root burn". The plants' health will suffer, often resulting in foliage damage and stunted growth. Flowering may also be diminished or stop.
Even without plant damage, over fertilization will encourage extra green lush foliage. Although that may seem healthy, it is not necessary natural for the plant. All the lush foliage, often with a failure to bloom, can attract leaf devouring insects as well as fungus and disease due to a reduced air circulation.
In order to appropriately apply fertilizer, it is important to clearly understand the needs of your plants. Some thrive beautifully on very poor soil. Some require frequent feeding to support plant health, blooming and reproduction. For many of our garden plants the best thing is regular, but minimal applications of a balanced fertilizer. Top dressing with compost is an ideal method of slowly delivering nutrients to your plants. Whatever materials and methods you use to feed your plants, keep an eye on the warning signs of over fertilizing. Plants are able to adjust to excess as well as too little nutrients for a while, but eventually will show signs of weakening.
Signs of over fertilizing:
Tips and edges of foliage may turn brown and dry
Foliage may appear wilted and yellow near the bottom of the plant
Leaves may drop with no other apparent symptoms
Growth may stop or slow down
Soil surface surrounding the plants may appear crusted with fertilizer
Keep in mind that these signs can also be symptomatic of other ailments. Nonetheless, when you are not sure what is causing problems for your plants, the best thing to do is withhold water and food until the plant sends clear signals. Reintroduce water first at the first sign of further wilting. Wait, even several weeks, before using a light fertilizer or compost top dressing. Monitor and be patient!