Understanding Fertilizer

Coming off our last blog about fertilizing, this week will we will dig deeper into understanding the different types of fertilizers. 

Let’s start with the numbers on the side of the bag –

Because who really understands what they mean?!  Hopefully after you read this though you will have a better understanding and at least know where to start with what you need. 

There are 3 numbers that tell us what the fertilizer is:

  • First number: the amount of nitrogen (N)
  • Second number: the amount of phosphate (P)
  • Third number: the amount of potassium (K)

A bag that reads 16-16-16 contains the proportion of each macronutrient in the bag; so this bag has 16% of each of the compounds found in fertilizer. These 3 nutrients are the key to feeding your plants, trees, shrubs and lawn.  But remember, every yard has different needs and that’s why there many variations of fertilizers.  For example, lawn fertilizers usually contain a high level of nitrogen to promote leafy growth but inhibit flowering.  

NITROGEN: is good for making leaves grow.

PHOSPHORUS: helps to improve fruit and/or flower production in addition to root growth.

POTASSIUM: is great for overall plant health.

When do you fertilize?

This can vary depending on where you live and your temperatures.  If you fertilize too early in the spring the nitrogen will promote rapid growth of cool-season weeds (dandelion, garlic mustard, white clover, etc.). If you fertilize too late in the fall, the grass is likely to be less hardy as cold weather approaches and more susceptible to injury. For maximum experience, you will want to fertilize once every 6-8 weeks during the active-growth period.

Let’s make this even simpler –

Break up the yearly requirement of nitrogen into the appropriate number of applications.  A general rule is to apply one or two applications in the spring, two or three in the fall and three over the summer.

PRO tip: no more than 1lb of nitrogen per 1,000 square feet with each application.


Early Spring – strengthen the roots [February – April; when lawns needs first cut]

Late Spring – keeps it well-nourished [April – June; 6-8 weeks between early spring feed]

Summer – protect and strengthen [June – August]

Fall – recovery from summer damage & prep for winter nap [August – November]

Associations and Memberships

Building Industry Association of Lancaster County Ephrata Area Chamber of Commerce Techo-pro Contractor Certified ICPI Installer