Cylinder & Rotary Lawn Mowers

Cylinder & Rotary Lawn Mowers

For the moment we will ignore the power source of the lawnmower and concentrate on the cutting systems as this is the most important for lawn quality. In general there are two different types of cutting systems for lawn mowers.

A cylinder lawn mower or reel mower has anywhere between five to twelve exposed blades at the front of the mower that rotate trapping and slicing the grass blades against a fixed bottom plate like a pair of scissors. The more blades there are the better the cut. The grass box is at the front.

Cylinder lawn mower.

The downside of this cutting system is that it works best on a low or short cut and will NOT cut long grass. This means frequent mowing, usually twice a week, but at least once a week in the lawn growing season to ensure a good cut.

Rotary lawn mowers have one very high speed rotating blade underneath. The blade ‘chops’ the grass on impact due to its very high speed. Most rotary mowers have the grass box behind with a few having an integral grass box. These mowers work best on a medium to high cut.

Petrol rotary lawn mower.

You can get variations on these such as ride on mowers or tractor mowers which are just larger ride on versions. The hover mower is very common domestically and are similar to rotary mowers but without wheels. Unfortunately they are not to be recommended offering none of the benefits of even the crudest rotary mower and often causing lawn problems. Some people still use hand mowers which are similar to cylinder mowers with you as the power source.

Quality of Grass Cutting

The quality of cut due to the slicing ‘scissor’ type action of the cylinder lawn mower, if maintained correctly, is superior to that of the ‘chopping’ or ‘smashing’ action of a rotary mower. However, a rotary mower with sharp blades and sufficient power produces a sufficiently good cut that most people would not know the difference; particularly when you take into account all the other imperfections that exist in a lawn.

The best way to explain the ‘quality of cut thing’ is to think about a bottle of wine. A very good wine might cost £20 to £30 a bottle. An extra-ordinary wine might cost £200 a bottle. How many of us could tell the difference? It’s no different with a good quality rotary versus a good cylinder mower.

Mower Maintenance

In addition, the blades of a cylinder mower need periodic and precise adjustment to maintain the quality of cut. If this is not done properly it will cause the mower to ‘chew’ the grass producing an exceptionally poor cut – far worse than a blunt rotary mower! If you don’t want to fiddle or are not mechanically minded this is as good a reason as any to stay away from cylinder mowers.

Mower Height Adjustment

Perhaps a more important difference between rotary mowers and cylinder mowers is the range and type of height adjustment. A quality cylinder lawnmower can ‘shave’ as close as 3/16” and can be raised up to about an inch without too much loss of mowing quality. A typical rotary lawnmower on the other hand won’t go much below 1/2” and can be raised up to perhaps 3” or even 4” without deterioration in cut.

The narrow range of height adjustment on a cylinder mower often means mowing at least twice a week in the growing season to keep within the ‘one third rule’. This also enables the mower to work properly and cut the grass cleanly. For your information, bowling and golf greens are usually cut every one to two days in the playing season!

The one third rule: never remove more than one third of the grass lead on any one cut

The type of height adjustment is either on a screw thread (offering infinite positions) or lever action with set positions. The number of settings is important because it determines the change in cutting height from one setting to the next. The more settings generally means smaller changes in cutting height which may also improve the highest and lowest settings. A mower with five settings is good with seven settings being excellent. Ride ons can often have ten or more settings.

Now, the typical lawn with its surface imperfections, perhaps poor drainage, shade, trees and roots, kids and dogs, even if of superb quality, with lots of TLC will always be greener and healthier cut at or above 1”………..

This means using a rotary mower!

Once you start mowing below ¾” your lawn needs to be ultra level to prevent scalping and should be the very fine bristle like grasses. You also need to know what you are doing so, as far as Lawnsmith is concerned, cylinder mowers are for serious amateur gardeners and lawn enthusiasts; rotary mowers are for normal people!