Fertilizer by the Numbers, Part 2

In Part 1 yesterday, we reviewed the NPK ratios, and what each of those macronutrients does for plants.  Now we’ll cover some other less familiar information regarding fertilizer use in the garden.  We’ll use Miracle-Gro’s various formulations as examples of the different options available commercially as a starting point.

• All-purpose plant food is 24-8-16. 
• Formula for tomato plants is 18-21-21.
• Lawn food is 30-0-6
• Rose formula is 18-24-16.
• Azaleas, rhododendrons, and camellias is 30-30-10.
• Bloom Booster Flower Food is 15-30-15.

All of these Miracle-Gro options are water-soluble synthetic fertilizers that contain ammonium phosphate.  Because they are water soluble they also leach easily out of the soil.  Overuse contributes to water pollution.  Overuse can also burn plants and damage the soil. 

Miracle-Gro also has their Performance Organics line.  The all-purpose formulation is 9-2-7; edibles is 7-6-9; bold blooms is 5-7-10. 

Those are the numbers for just two lines from one company.  Throw in the options from several other businesses, and it’s easy to get confused.  And then confused people are more easily swayed that they need XYZ product to improve their results. 

Then add to the confusion that among serious gardeners and plant enthusiasts, a debate rages regarding the use of specialty fertilizers.  You have marketers persuading a susceptible public that the best results will be obtained by using specific formulations.  It seems logical to feed tomato plants exactly the nutrients they need to get the most bountiful harvest, right? 

However, the problem with applying set formulas for specific plants is that these formulas are only correct if the soil test shows that this is the exact ratio needed.  In other words, none of the Madison Avenue advertising executives are taking into account the needs of your particular soil.  Is your soil already high in nitrogen because you grew a lot of beans in that area last year?  Or is it depleted of phosphorus because of all the flowers you had growing there?  That’s why having some soil tests conducted is advised.  “They” say you should only add the nutrients that your soil actually needs, and it’s a good point.  And that’s where the arguments usually end.

Unfortunately, little mention is made of adding exactly what is needed to the soil to grow whatever plants you want to grow there that season.  I can test my soil and add whatever soil amendments are recommended to bring my soil to acceptable levels of nitrogen, phosphorus, and potassium.  But what if I want to grow blueberries and need much more acidic soil? 

It seems to me that it’s critical to consider both amending the soil to make it productive, as well as being able to feed specific plants exactly what they need to thrive.  Most vegetables will be happy with average soil conditions, but there are the outliers like elderberries, blueberries, and peppers that really need a lower pH soil to thrive. 

Remember, we are or soon will be in a survival situation.  We may have to resort to less than ideal choices for fertilizing our fruits and vegetables.  We might be relegated to using synthetic fertilizers or having to combine different packages to achieve the levels of fertilization that we need.  Whatever we do, we don’t want to kill our plants or destroy our soil. 

And that brings us to the shelf life of fertilizers.  After all, we store food, water, vegetable seeds, and medical supplies.  It only stands to reason that we should also store some fertilizer in order to grow our vegetables in a crisis.  So how long do fertilizers last?

Various sources indicate that most fertilizers last several years under ideal conditions.  And that means dry and not too hot.  So the garden shed probably isn’t the best place to store it.  Ugh.  Also, apparently liquid fertilizers have a longer shelf life than dry—up to 8-10 years.  It was also noted that liquid fertilizers go rancid when they go bad. (And at least they were honest in acknowledging the difficulty in determining when a fish fertilizer goes rancid.)

Links to related posts:

Fertilizers by the Number, Part 1

References:

https://homeguides.sfgate.com/npk-ratio-miraclegro-purpose-87412.html

https://www.thespruce.com/best-fertilizers-4154249

https://whyfarmit.com/does-miracle-gro-expire/

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/fertilizer-numbers-npk.htm