Today lawncare mastery is answering a reader question, the question being:
Can my fert machine cause fertilizer to spray, unnoticed by the driver, in amounts which will result in burn patterns of different shapes and sizes? – John
It is a good question although it can be difficult to answer quickly. The machine can cause fertilizer burns in very subtle ways that the operator may not notice until it is too late. There is a caveat though, the burn patterns should be fairly consistent in shape, if it is being caused by fertilizer, because the mis-delivery of fertilizer will be consistent- more on that in a moment. First let’s look at a few common causes.
The impeller is not being cleaned off regularly
If the operator is not cleaning the machines impeller off daily, sometimes more often depending on how much or what inert a particular product contains, it will begin to cake up into lumps on an impeller. This will result in the fert coming off the impeller in unexpected patterns or, occasionally, just falling straight down. The burn marks will often be in straight lines, following the path the machine took. The burn itself can take up to 2 week to appear.
The impeller stopped spinning
It may seem obvious but I have seen it happen time and time again. If the cotter pin breaks or the impellers motor stops working, without the operator realizing, then fert will just pour out and drop straight down. Once it happens it will be noticed by the user right away because fertilizer will not be flying out in every direction. The burn will be a large circle right where the fertilizer was dumped. Even if you attempt to clean it all off the ground a large of a concentration in one spot, however brief, almost always burns the turf.
The impeller shaft is loose
Inside of the hopper where the impeller is attached to the motor there are two machine screws with hex heads. These screws tighten the impeller shaft to the motor. If the screws come loose the impeller shaft may spin but intermittently miss a beat, you may not even notice it but it will cause fert to drop in one place and cause a burn.
Not using a hopper cover
If the machine is run without using the cover then fert will spill out when hitting a bump or jumping a curb. This almost always causes some burning or stress in those areas. If your cover has worn down or has holes in it replace it immediately, lesco sells replacements.
Filling your hopper over turf
It is inevitable that when filling your hopper some fertilizer will spill to the ground. To be safe and avoid burnt spots always fill up somewhere safe.
Other problems that may cause a burnt appearance
In all of the above situations you should be able to see excessive fert in the burnt spot if you look closely, dig down through the thatch to the soil surface. The spots or burnt areas will be consistent looking rather than sporadic. If you are not able to spot any fertilizer in the burnt areas it may be a disease or another abiotic problem.
A gas leak or filling gas over turf
Gas will burn turf although it may not kill the roots and only cause a tip burn
On a zspray herbicide can leak out of loose fittings or your spray nozzles due to worn parts. Also nozzle leakage can be caused by leaving the valve to the spray reel open ( as noted in the lt rich manual). To check for leaks run the machine over a dry area of your shop and watch for any wet spots forming.
This is a big one and may be the culprit in the readers question. If the burnt areas appear to be in random shapes and sizes it leads me to think it may be a disease, because a fertilizer leak will tend to be consistent and form the same burn pattern every time.
If you think it is caused by fertilizer try to get close to the ground and look for fertilizer pellets, they will be there, it can take weeks for their complete breakdown. If you do not see any then I would begin to question whether it is a disease. It can take a long time to develop an eye for disease symptoms but with a well written disease guide that contains plenty of color pictures you can begin to deduce the exact cause. Best of luck to the reader on solving your problem and thank you for submitting a question. If you have other landscape questions feel free to ask on the question submission page.