Understanding fertilizers – 9 varieties


Understanding fertilizers: Synthetic

  • Urea (synthetic) – By far the cheapest fertilizer, extremely soluble in water so will readily leach in a wet spring. Ultimately converted into ammonium or nitrate to be taken up by the roots where it will require stored energy to assimilate(be used). Urea is also susceptible to volatilization where it is converted into ammonia gas, this primarily occurs at the surface and warmer weather accelerates this process.
  • Ammonium (synthetic) – Comes in many forms, ammonium is half of a “salt” meaning you’ll find it as ammonium sulfate or ammonium nitrate. These fertilizers have an incredibly high salt index which can make it difficult for turf to take up moisture or other nutrients and is the same reason why fertilizers “burn”. Ammonium can be taken up by the plant but needs to be detoxified once absorbed and again, it requires stored energy to be assimilated. Ammonium sticks to clay and organic matter in the soil and leaches less than urea or nitrate.
  • Nitrate – Extremely soluble in water meaning it readily leaches in the wet spring. Another salty fertilizer that is usually found is paired with ammonium, potassium, or calcium. Plant seeds may be more likely to germinate in the presence of nitrate and for early germination like knotweed & crabgrass, this may lead to undesirable weeds.

Understanding fertilizers: Organic

  • Compost (organic) – Not a “traditional” fertilizer but is often confused to be. Compost is a great way to add organic matter (true fertility) for healthier soil but in terms of NPK(numbers on fertilizer bags), it’s quite low.

  • Plant matter (organic) – This can be anything from corn gluten to fermented soymeal. These products are on the expensive side in terms of NPK but deliver several benefits to your lawn that synthetic can’t. These are generally slow-release nutrients because they must be broken down into nitrate or ammonium or amino acids which can take a while.
  • Amino acids (organic) – These are processed plant residues that can be taken up by the plant roots and have special properties in the soil such as the ability to make other nutrients more available to the plant.
  • Biosolids (organic) – Biosolids are digested municipal wastewater sludge that is sterilized and dried. This is a slow-release fertilizer that is not prone to leaching and adds valuable organic matter to your lawn if you can stand the smell.
  • Blood meal & guano (organic) – These products are more similar than you may think, both are relatively quick-release fertilizer sources of nitrogen(what you’re paying for) this is because they are both high in naturally occurring urea. These are both very expensive sources of urea and can burn if applied at too high a rate. The “eco-friendly” benefit of these products is highly controversial.
  • Biostimulants (synthetic/organic) – Synthetic biostimulants like rooting hormones aren’t typically used by turf professionals and won’t be discussed. Organic biostimulants are an endless list of fancy compounds but be cautious, these products rarely deliver on promises and can cost a fortune. You may have heard of kelp or maybe liquid aeration but these products just can’t be applied at the quantity needed to show benefit because of their cost. That’s not to be said that there aren’t a few that show some promise like silicic acid, or kinetin but in these cases, they need to be applied weekly to see results.

What should you choose?

There is no one size fits all product for proper lawn care, choosing a variety of products will have the best results. Stick to quicker release in the spring and slow in the summer while choosing products that won’t leach during wet periods of the year. OR choose Renew-a-lawn as we do exactly that with your best interest in mind.

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