All plants should be fertilized, which is why it is so surprising that most gardeners do not use fertilizer on their crops. Plants must be fertilized because most soils don’t provide essential nutrients that are required for optimal plant growth. Fertilizer helps replenish nutrients in your plats so that they have the food they need to prosper. Just as children need food to grow, your crops need food in order to grow too!
There are nine primary nutrients that all plants require: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, carbon, hydrogen, and oxygen. The last three (carbon, hydrogen, and oxygen) plants can get from both air and water. The other three must come from another source. Nitrogen is vital for plants making protein and producing tissues, but it is in short supply so plants are genetically made to absorb as much as possible. This means if a plant gets too much nitrogen they can grow large but without producing.
Phosphorus is vital for root growth, setting buds/flowers, vitality, and seed size. Generally, plants require a soil pH of 6.5-6.8 to properly absorb phosphorus. If fertilizer does not work in getting your plants enough of this nutrient then remember that both the organic matter in the soil and the activity of organisms within the soil can also increase phosphorus in your soil. Potassium helps plants strength and endurance. It facilitates the creation of carbs in the plant (regulating metabolism) and helps it with immunity.
The other three nutrients—calcium, magnesium, and sulfur—are only needed in small amounts. Calcium helps the membranes of cells within the plants and neutralizes toxic materials that invade a cell. It also advances soil structure: calcium is vital when it comes to binding organic and inorganic particles together within the cells of your crops. Magnesium is metallic: the only one found within chlorophyll. It is critical for plants processing sunlight, without this skill plants die off quickly. Sulfur is great because it is a component of multiple proteins, something extremely healthy for crops.
It is important for you to pick an all-purpose fertilizer that will provide all these nutrients to your crops. Make sure your plants are properly fed this season so that they can properly feed you come fall.