Yes. You Should Fertilize Plants During the Summer

Many people believe you can't or shouldn't fertilize during the summer months. That is incorrect. Fertilizers are important to apply when plants need them, not according to the weather. The reason people are told not to is because fertilizers can be more dangerous to plants during hot summer months.

This is how you can and should fertilize during the heat. It is not magic. It is common sense.

 Ammonium sulfate can burn plants, is fast in its release and dissolves totally in water. I use it but you must be very careful using this fertilizer in the summer.

The major problems with fertilizing during summer heat is the combination of high temperatures and fertilizer salts. Salts in fertilizers can be damaging alone but in combination with high temperatures, they can be lethal. The amount of fertilizer you can safely apply is much higher in cooler months than in hotter months. You are not going to change the temperatures, but you can apply less fertilizer.

Rule No. 1. Apply less fertilizer during hot weather. 

Salts are all around us. They are in the food we eat. They are in the water we drink. They are in the soils we use to grow vegetables. Most organic fertilizers release fertilizer salts more slowly than conventional fertilizers. Not always, but generally speaking. So using organic fertilizers is usually a safer thing to do than using conventional fertilizers.

Rule No. 2. Use organic or slow release fertilizers during hot weather.

Fertilizer salts are salts. Salts can damage plants in two ways. First, drying out plant roots and stems through dessication or pulling water out of the stems against the desire of the plant to keep water inside the stems. Salt applied to living tissue pulls water out of the tissue. This type of damage to plants is much more severe when soils are dry. Never apply fertilizers to dry soils during summer months. When you are finished with a fertilizer application, water the fertilizer into the soil.

Blood meal is an organic fertilizer, safer to use than ammonium  sulfate but you still need to be careful.

Rule No. 3. Irrigate soils first. Apply fertilizer next. Then water in the fertilizer.

Fertilizers applied 1 to 2 inches next to the stems of plants can damage or kill. Salts in fertilizers pull water out of stems. If fertilizer is accidentally applied too close, don't panic. Either scrape it a few more inches away from the plant or push the fertilizer away with a stream of water and water it in. Apply fertilizers near the water source and no closer than 4 to 6 inches from small plants. Whether you think dry fertilizer landed on plant leaves or not, it is always safest to wash the leaves with water after a fertilizer application.

Rule No. 4. Keep applied fertilizer a safe distance from plants.

Temperature is important when fertilizing plants. Apply fertilizers in the cool morning hours or when there is a break in the summer heat.

Osmocote is a slow release conventional fertilizer but a safer fertilizer to use in summer months.

Rule. No. 5. Apply fertilizers to plants during the cooler times of the day.