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By now people have gardens in the ground and are hopefully thinking about the nutrients that the plants will need to survive. Let’s talk about some of the different sources of nutrients that can be used for plants in the garden.

First off, I want to clear up that fertilizers and plant nutrients are not plant food. Plants make their own food by photosynthesis, which is converting light into chemical energy that plants, and the animals that eat them, can use. Nutrients like nitrogen, phosphorus, potassium, iron, magnesium, would be more like vitamins in our diet. They are essential for specific processes that plants do.

Organic fertilizers include products like bonemeal, bloodmeal, or milorganite. These are fertilizers made from natural sources. A lot of people like to use these because they are made from natural sources and are recycling nutrients so that they don’t go to waste. One thing to keep in mind about organic fertilizers is that some of them have an odor. This can be beneficial as they can be used to keep wildlife away from plants temporarily. The nutrients that are in organic fertilizers are not immediately available to plants. The fertilizer must break down for the nutrients to become available. Organic fertilizers also tend to have a lower concentration of nutrients compared to synthetic fertilizers.

Compost is a great soil amendment. However, as with any amendment we should make sure that what we are growing also has native soil too. If there is no soil, the nutrients will leach out of the compost over the winter. The nutrient concentration in compost is very low compared to fertilizers. The compost also has to break down for the nutrients to become available. Therefore, it is advisable to use compost with native soil and other fertilizers for best results.

Worm castings carry concentrations of nutrients much higher than compost. Worm castings are made by using worms to consume organic material and then collecting the leftovers. Worm castings are very beneficial to plants and tend to help grow very healthy plants. You do have to watch out for volunteer seeds in worm castings. There is no heat involved in making worm castings so any seeds that are put into the worm bin will come out the other side too.

Synthetic fertilizers are the most common form of nutrients for plants, and have been for a long time. If you go to the garden center and buy a bag of 10-10-10 or 34-0-0, most likely that is a synthetic fertilizer. In these products the nutrients are immediately available to the plant when they are watered in. They also tend to have the highest concentration of nutrients, which makes them common in large scale production. They also require a lot of energy to create.

In America all fertilizers are required to have a guaranteed analysis. This guaranteed analysis indicates by percent weight the concentration of Nitrogen-Phosphorus-Potassium. The numbers are always reported in this order.

Hopefully, now you know a bit more about the fertilizer options that are out there and what fits best for your situation. If you have a question about fertilizer, contact your County Extension Office or email me at Jacob.Williams@uga.edu.

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