Intro to when to fertilize

Any time you decide to use fertilizer, the question that needs to be answered is when to fertilize.  The time and schedule that you use is critical to your plants or lawn.

Many of us find that the answer to this question is not as simple as it seems; it is completely dependent on the plant or lawn that you are trying to fertilize.

This website is dedicated to this single question of when to fertilize.  This is a work in progress so please look through the categories for the type of plant, tree or lawn you are trying to fertilize.  If we don’t have an article yet, be sure to ask the question on our forum!

Here are some general tips for a fertilizing schedule.  For plants, spread your fertilizer applications into consistent small doses.  Make sure that you don’t fertilize without watering your plants thoroughly before application.

Plants, trees, and lawns need certain nutrients to survive. Carbon, Hydrogen, and Oxygen are elements that are plentiful for plants and lawns in their natural habitat.  However, elements like nitrogen, Phosphorus, and Potassium are not readily available to plants once depleted.  For this reason, when deciding when to fertilize, it is important to test the soil to determine what kind of fertilizer you need and also how often you need to apply it.  This is because different plants will use up the nutrients in the soil at different rates.

So, since we don’t have all the articles on when to fertilize yet here is an outline to help get you started.

Before we start please note that most fertilizers will tell you the ratio of the different elements it contains.  They will come in three numbers such as 5-10-10.  The first number N is for nitrogen, the second one P is for Phosphorus, and the last one is K which is for Potassium.

Fertilizing in January:

In January the rule of thumb is not to fertilize.  You would not fertilize your lawn in January because most likely at this time of year depending where you live your lawn will be dead and all the fertilizing will be a waste of money.  The only exception is if you over seeded your lawn with a cool season grass.  If this is the case, you might want to fertilize in the middle of January.

Also, it is the same story with Roses, Perennials, Bulbs, Annuals, trees, and shrubs.  January is not the best time to fertilize so save your fertilizer and your money for when it will really make a difference!

Fertilizing in February:

In February it is too early to start fertilizing trees, lawns or flowering shrubs.  However it is ok to start fertilizing things such as lawn plants and fruit plants.  Depending on where you live, February might still be too cold to start fertilizing so be careful and if you have any questions ask on the forum!

Fertilizing in March:

In March hopefully you are starting to see the first signs of spring on its way.  In this month you can finally start to fertilize your lawn.  You should probably stick with a slow release fertilizer and not over do it.  This is important!  You don’t want to shock or damage your lawn growth by over fertilizing.  A good fertilizer ratio for this month would be 3-1-2.

In March you can also start to fertilize your trees using such things as fertilizer spikes and granular fertilizer.  For shrubs, March is the month of the year!  When you fertilize your shrubs here is a money saving tip.  Rake the mulch out from under the shrub before applying the fertilizer.  This will keep you fertilizer from getting absorbed into the wood of your mulch.  You can also start to fertilize your flowers in March, but make sure that they are well established and that you don’t fertilize them too much.

Fertilizing in April:

If you didn’t fertilize in March, because your climate was to cold, then April is a good month to fertilize instead of March.  The main thing is that you don’t want to fertilize when it is too cold.  So, depending on where you live April might be the time to do the recommended fertilizing for March.  In short, what was said for March applies for April.

Fertilizing in June and July

In June and July a slow release fertilizer for your lawn, a 3-1-2 ratio, is still your best option.  This is when to fertilize grass that you planted in early in the spring.  In these months you want to fertilize things that were planted in the late or even early spring that are still getting established.  This includes shrubs, bulbs, flowers, and the like.

The summer is also a good time to fertilize your trees.  Trees can sometimes benefit from a fertilizer boost to help them stay fresh till fall.

Fertilizing in August through September

If your lawn starts to look yellow, this would be a good time to fertilize with liquid iron fertilizer.  For liquid iron fertilizer you only need to apply liquid iron once a year.

Fertilizing in October through November

In October and November, you need to make sure that your plants are ready for winter.  As, stated before, a lot of the recommendations are dependent on where you live.  For instance, if you live up north, you might need to fertilize earlier in the fall.

One thing to do in October or November is use a winter fertilizer on your lawn.  There is not a one type fits all ratio for winter fertilizers.  Since this the case, just check the labeling or ask at your local garden store, or the forum.

For trees, October and November are a good time to check for a lack of iron.  The best way to know if your trees need help is to look for yellowing in the leaves.  Liquid iron might be a good choice of fertilizers to apply to your trees but don’t overdo it.  Fall is the time that the leaves change color, so don’t waste a lot of money trying to keep them green.

As a side note, fall is not the time to fertilize your plants.  The major exception is with fall blooming flowers.  By fertilizing your flowers it will increase their strength and prolong their bloom period.


Hopefully you’ve got some idea of the answer to the question “when to fertilize.”  For more detail on a particular plant, or type of grass please ask on the forum.

Also, if you are a fertilizer expert, you are more them welcome to write articles and share your ideas.

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