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Love the Rain but not the Yellowing Lawn? Let’s Fix That!

Oh, it’s so nice to say the ‘W’ word without environmental whacko’s blowing their top assuming it’s being wasted.   You’d have to be living under a weather rock to know that the drought is officially over in California.  What a sigh of relief to look at those mountains to see them packed with snow.  We, the voter, planned for this epic amount of snowfall and rain.  Did you know that?  On November 4, 2014 you voted for the Water Bond Prop with $2.7 billion earmarked for water storage (click here to read more) .   Did they build the water storage facilities?  Nope!  Oddly enough the money is just sitting there.  The politicians haven’t even lined their pockets with it, yet.  I say we excavate the front and backyard of those politicians’ homes, line them with plastic and use their properties and a holding facility until they the get real ones built.  Nearly 10 years later they should have had something in place – even if was a big bucket! But, in the meantime let’s party….WE HAVE WATER!  Don’t get cocky though we need to be good stewards of the water and strategically place it.

As wonderful and it’s been with all the rainfall southern California has received an interesting phenomena is happing to your soil – nutrients have been leached out.  Nobody is going to argue that rainwater isn’t the purest form of water dropping from heavens above.  However, too much of a good thing will manifest problems that your plants will suffer from.  You’ll notice it in your lawn before your plants.  Let’s explore why too much rainwater is good but bad at the same time and what to do about it.

Cool Clear Water!

As Johnny Cash once sang Bob Nolans song we know rainwater is cool and clear.  Rainwater is pure H2O without any minerals  (ie. sodium, potassium, calcium, fluoride).  Straight from the heavens it falls without touching rock, dirt and contaminates.  Rainwater is like a home reverse osmosis water system but from the sky and a bit on the alkaline side.

Fun Fact:  When an inch rainstorm falls on a 40’x70’roof it can catch and release 1,743 gallons of water. Don’t drink it though because there is soot, bird poop, bacteria, viruses, parasites, dust, smoke particles and other chemicals on that roof, it’s not potable. But, it’s okay for your plants so start filling up those water balloons if you don’t have any buckets!

It’s Greener On The Other Side.

After any rain our lawns look greener and rightly it should. Rain is good for our lawns.  Our atmosphere is loaded with nitrogen, the greening agent lawns love – nitrogen gas (N2), ammonium (NH4), and nitrates are all found in small amounts in rainwater (NOx).  As rain falls it collects what it can but it’s not enough because have you noticed that soon after lawns turn yellow really fast?

Grass will absorb moisture through their leaves and roots.  Water doesn’t stay on the leaf surface for long so gravity pulls the water to the soil surface.  The structure of your soil and your neighbors is much different from each other due to the percentage of mineral content is has: sand, silt, clay and organic matter. This, in turn, determines how much air space between each mineral allowing roots and water to fill those spaces.  Clinging to those minerals are nutrients.  When a lot of water passes by the minerals it basically washes or leaches the nutrients right off so plant roots can’t lick them up the feed itself.  The result is yellowing.  Soon the plant gets weaker and weaker.

It’s All About the Science.

Earlier we discussed that rainwater is on the alkaline side.  In other words it has a higher pH which measures alkalinity and acidity on a scale of 0-14 with 7 being neutral.  Most plants want to be in the range of 5.5-6.5 (acid).  Lawns can handle a 7.0 pH but if the rain is already on the alkaline side it’s being added to an alkaline soil which will raise the pH.  Here’s the link of why pH is so important:  too much of either a high or low pH means that the some of the nutrients might be clinging to the soil particles that haven’t been leached away cannot be unlocked within the soil structure and released to plant roots.

Another thing to be alarmed with is how fast the grass will grow with one day of warm weather.  Grass will bolt and you might be looking at a jungle!  Even worst rain will reach down to the depths of the earth to wakeup dormant weed seeds.  It’s not uncommon for a beautiful lawn to be overtaken by the weeds.  So, let’s make a plan.

Plan of Action.

At the first sign of dry weather mow the lawn!  Even if it’s between rain storms cut it to its recommended length like you normally would.  If the lawn is out of hand try mowing at the highest setting then moving lower the second or even third time around if needed.  Don’t get wigged out if the cut looks horrible and a soccer game was just played on it.

The lawn will be a bit chewed up.  When the lawn is over six to eight inches tall you might want to rent a high-wheel lawn mower.  This type of lawnmower has the ability to cut tall grass over a foot long.  If it’s taller yet get a weed whacker to cut it to a manageable height to get the lawnmower on it.  This job is going to be messy.  You’ll be staining your shoes and pants up to your ankles the color green (you just have to love that chlorophyll).  And, the grass might be wet and certainly the soil is saturated.  Keep in mind this has to be done because lawns want to be mowed.  This simple act will encourage it to grow stronger.

Pro-Tip:  Regardless of how a seasoned pro applies a granular fertilizer (handheld, drop or hopper spreaders) to make sure they don’t miss any spots they might apply it at half-rate walking in one direction then walk in the opposite direction to overlap any areas that they might have missed which will evenly give the required coverage of fertilizer.

Let’s Eat!

The nutrients leached through the soil strata have to be replenished.  The best way to get this done is with a granular fertilizer.  Marathon All Season Fertilizer is the key for getting this done because its magic works in cool weather because the high nitrate levels it provides and relieves yellowed lawns so they can bounce back into the green.  Of course the phosphorous in the fertilizer is a perfect dose to what build a turfs root system and potassium helps the durability of the lawn stand up to the leaching it went through.

For lawns that were just seeded and germinated we want to gently feed it.  After the first mowing let’s apply the Marathon Sod & Seed Starter Fertilizer.  It has a bit less nitrogen so not to burn the young’uns but the phosphorus and potassium is available to nurse those seedlings.

Final Thoughts.

Living in Southern California the 17th century nursery rhyme “Rain, rain, go away” hasn’t been chanted so much in the last 120 years.  We’ve seen epic rains to the point I’m thinking about building a miniature ark!    We all realize there’s a serious undertone that we need the water and we need the snow pack.  More importantly we need to call our local water agencies and politicians and hold them accountable for ignoring our 2014 Water Bond Proposition and find out when the lakes and cisterns are going to be installed.  It’s a good thing our lawns are yellowing because of the rain.  We now know how to fix it.  Now, we need to capture the rain just like we voted for.


Nick Federoff Horticulturalist for PBS|KLCS TV, CBS|KCAL

News and Syndicated Radio Talk Show Host