Last Updated on February 18, 2021

When To Use Triple 13 Fertilizer

First, what is a triple 13 fertilizer?  What does that mean, though, triple 13?  How, when, and where do you use it?

What Minerals are in a Triple 13 Fertilizer?

When you shop for fertilizer, you will see that every bag will present three numbers separated by a dash.  A 13-13-13 fertilizer is a general purpose, quick release and fertilizer that must be re-applied frequently to be effective.

The 3 numbers represent the percentage of the nutrients nitrogen, phosphorus, and potassium in the fertilizer.

These 3 nutrients are needed in relatively large quantities by most plants for good root development and plant health.  The first number refers to the nitrogen content, the second to phosphorus content, and the third to potash.

Phosphorus is often referred to as phosphate, and potassium is frequently called potash.

You might also see them on bags abbreviated as N-P-K.

Where Can You Use Triple 13 Fertilizer?

Many bags of 13-13-13 fertilizers will promote it as balanced and all-purpose, suitable for lawns and flowers.  Some, too, will suggest it is ideal for vegetable gardens, shrubs, hedges, and trees.

It’s a fast-acting fertilizer that will give a quick green-up instead of a slow-release, slow-acting version.  As such, frequent re-applications are needed anywhere it is used – lawns, gardens, flowers, shrubs, hedges, and trees.

How To Apply Triple 13 Fertilizer

For an established lawn, triple 13 fertilizer should be applied just before spring green-up or the beginning of the growing season.  As a very general rule, 10 lbs of fertilizer per 1000 square feet of lawn should be applied.

After that first application, lawns should be top-dressed with 7 lbs per 1000 square feet every 8-10 weeks during the growing season.  Your lawn’s greenness will determine when to apply during that 8-10 week range.

In order to avoid fertilizer burn, never apply the 13-13-13 fertilizer to wet grass.  So, avoid first thing in the morning when dew is likely to have formed on the grass blades, and never after watering.  But, always water in the application immediately after spreading.

For a new lawn just planted, increase the first application to 15 lbs per 1000 square feet.  Re-applications during the growing season can be at the same 8-10 week interval.

One acre is 43,560 square feet.  If your lawn is that massive, well, first of all, you really should have a riding mower.  As regards fertilizer application, the ratio of 10 lbs of fertilizer per 1000 square feet still applies.

So, you’ll need roughly 43 lbs of triple fertilizer per acre per application, so 3 to 4 – 40lb bags will be needed for your lawn growing season.

Other Triple 13 Fertilizer Applications

Fertilizer manufacturers recommend triple 13 fertilizers for flower beds, shrubbery, hedges, and trees, in addition to lawns.  The amounts and timing of applications differ for each, and you should read the suggested uses on the bag.

Garden applications will be a bit heavier in the first, early season, pre-planting spread than an established lawn will need.  Flower bed, shrub, and hedge applications will be a  bit lighter.

Tree applications should be measured by diameter and applied deeper into the soil surrounding the tree.

When applied correctly and in the proper ratios, triple 13 lawn fertilizers will help the health and root development of plants, trees, and grass.  Again, follow the directions on the bag you purchase.

When a new growing season arrives, have your plans ready, including your fertilizing regimen.

A triple 13 fertilizer will be a good choice for your lawn when used correctly.  The result will be a quick greenup that you can revive during the growing season with re-applications.

GRF 13-13-13 NPK Granular Fertilizer
  • 🌱 NEW BAG DESIGN!!!
  • 🌱 Universally used macro-nutrient for starting off your harvest. Mix with our GRF Soluble...
  • 🌱 Don't just give your plants the basics, give them the BOOST they deserve!
  • 🌱 Slow release, set and forget. Good for months without having to add again!

Author: Matt Hagens

Matt Hagens

Hi, I’m Matt the owner of Obsessed Lawn. I love to be outside working on my lawn, planning my next project. I created this website to help people like you find the best products for yard care and great advice. Learn more about me and find me on Facebook.