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Nutrient Management: A Recipe for Successful Growing

To be the best grower you can be, you need to have a good understanding of the essential nutrients for plant growth. Nutrient management means getting the most “bang for your buck,” while not wasting money and time by over-fertilizing or using the wrong fertilizer at the wrong time. Most of you know about N-P-K (nitrogen, phosphorus and potassium), but do you know that there are 15 other nutrients that are considered essential to plant growth?

Nitrogen, phosphorus and potassium are considered macro nutrients, or nutrients that the plant needs in large quantities. There are three secondary macro nutrients and twelve other nutrients called micro nutrients. Plants need these in smaller quantities for optimal growth. Today we will be looking at some of the basics in nutrient management to make this season’s harvest the best yet.

pH meter

N-Nitrogen is an essential part of the photosynthesis process. Nitrogen is directly associated with top, or vegetative growth. Use a fertilizer higher in nitrogen for leafy crops such as lettuce. Nitrogen deficiency symptoms include stunted growth, delayed maturity and chlorosis.

P-Phosphorus is also critical for photosynthesis, as well as respiration. It is required in lesser amounts than nitrogen or potassium. It helps create a strong root system for the plant and is a key part of fruit and seed production. A phosphorus deficiency causes purplish leaves, stems and branches, stunted growth and decreased yields. Use larger amounts of phosphorus for increased root and fruit growth.

K-The last of the macro nutrients is potassium. This valuable nutrient is important for water retention and is key to starch and protein formation. Plants that are experiencing low potassium levels will likely have reduced yields, spindly stalks, curled older leaves, and a weak root system.

Ca, Mg, S, Si, and Mn-Moderate levels of calcium, magnesium and sulfur should be provided to plants. Silicon and manganese should also be present, but in smaller amounts. Calcium builds strong cell walls and assists in nitrogen uptake. Magnesium is for chlorophyll and vitamin formation. Sulfur is for amino acid production and flavor in onions and other vegetables. Plants also utilize small amounts of silicon for fungal immunities and manganese for photosynthesis. Lack of these minerals will result in yellowing of older leaves, deformed leaves and stunted growth.

Micro nutrients-Boron, copper, chlorine, iron, manganese, molybdenum, sodium, nickel, selenium and zinc are all considered micro nutrients. These are needed in minute quantities, but are not any less important to the plant’s overall health. Symptoms of micro-nutrient deficiencies are often quite similar to macro-nutrient deficiencies and can also be cumulative.  While micro nutrients are indeed essential in small quantities, all are toxic to plants in large amounts.

Boric Acid

Now that you have an understanding of which nutrients are essential to plant growth and the nessesary quantities, you should send in a soil test (or a leachate water test if you are growing hydroponically).This will help you see what elements you are missing and add them to your fertilizer program. Do-it-yourself kits can help you determine the macro nutrients you are lacking, but a more thorough analysis can help you measure micro and secondary nutrients.

Testing Kit

pH management-Even when using the best fertilizer on the market with all the right nutrients, if your pH levels are off, your plants will not thrive. Think back to seventh grade science class and the lesson on pH. If you recall, pH is measured on a scale of 0 to 14 with 7 being neutral. Plants prefer a slightly acidic soil or growing solution. Most plants prefer 5.8 to 6.2 pH, but we aim for 6 in our management practices. If your soil or growing solution is around 6, the plant is best able to use all of the available nutrients. If your pH is too low or too high, the plant is unable to utilize the nutrients as effectively and you will notice a loss of plant vigor.

The pH in our Dyersville, IA location is almost 8.0! We use a sulphuric acid solution to bring our water down to an acceptable range, but you can also use vinegar or citric acid if you are growing organically. Most people have a high pH issue, but if you do find that you have a lower than normal pH, you can use sodium bicarbonate (baking soda) to increase it.

Testing meter

The building blocks of a healthy plant are the nutrients that they need to grow. If you want to be the best grower possible, take further steps to help you fully understand your fertilization program. Get your water and soil tested by a lab annually. Especially with the drought of late, your water source is prone to change, creating problems that you may not have known existed.  Your local extension agent can give you details about samples required for testing and where to send them. I also recommend getting a handheld pH/EC meter. This can help you get a better understanding of what you are feeding your plants and make you more successful. You can easily test your high tunnel soil, potting mix, fertilizer water and water source as often as you need to optimize your fertilizer regiment. By maintaining a proper pH, your plants will use the fertilizer efficiently and you will be the envy of your garden club. Now let’s get growing!

Do you want to learn more about hydroponic growing? What would you like to see Sam write about next?

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