Michael,
The fifth green at Merion is amazing.
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For those interested in the original construction process of the greens, here is a bit from Hugh Wilson writing in 1916:
Soil.
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Our error in building the greens was a failure to open up the soil sufficiently and take care of the drainage. When we built them, they were all raised above the surrounding ground level so as to get good surface drainage and freedom from wash. We also forked in about eight tons of manure to a green and added about five tons of sand (not nearly enough) with a layer of leaf-mold, sand, and soil mixed in about equal proportions for the seed-bed. As was stated before, the results were good the first year, and it was not until the end of the second year that we noticed much deterioration in certain of the low-lying greens. In the fall of 1913, two years after seeding, the grass started to die in these greens and although we nursed them carefully, having noticed early in the summer that they were weak, all our efforts with fertilizer, water, and care were of no avail. Opinions differed as to the cause and treatment. Finally, we determined that as we could obtain a quantity of good turf from our old course, we would dig them up and resod them. We started November 1 and our first decision, after a thorough investigation of the soil conditions, was to add a lot of sand and gravel, and also to under-drain them with tile. In order to lessen the cost, we dug the gravel out of the stream near the greens and covered the present soil to a depth of four inches. To this we added ten tons of manure; this was thoroughly worked so that it was a complete mixture of soil, gravel, and manure, and at this point may I strongly emphasize one thing — that experience has taught us that, whenever manure, sand, or any such substance is added to the soil, the mixture must be made as thorough as possible in order to obtain really good results. We then put in drains of three-inch tile, eighteen inches deep and twelve feet apart, with as big a fall as possible. On two greens it was possible to keep both ends of the drains open and these were protected by a fine wire netting. After this we tested our soil by flooding the green so as to see if it would take care of the excess of moisture. It is very difficult to say just how much sand or gravel should be added to a soil to make it right. The gravel should only be used for the lower stratum of your green, and sand for the upper three inches, as gravel will spoil the putting as well as the mowers. Naturally, the depth depends on the size of the gravel. The ideal is a soil that will absorb enough moisture to take care of the grass roots in dry weather, that will raise the moisture in time of drought from the lower levels, and that will dispose of the excess. The latter can be tested out by flooding. Care must be taken, however, not to add so much sand that the soil will not retain enough moisture. Probably the simplest test is to squeeze the soil, when damp, in your hand and if it falls apart it is too sandy, but just previous to this stage it is about right. This I appreciate is a crude way of explaining soil structure, but is used because of the absence of a better one. The tremendous importance of soil structure cannot be over-emphasized. If it is bad, it does not make any difference how much you may fertilize or what you may do, you cannot have satisfactory greens. By satisfactory greens are meant greens that are in good shape most of the year and will stand a lot of wear. From our experience, soil structure is the foundation of greenkeeping, and it is a simple matter, and relatively inexpensive, to make proper soil conditions when constructing greens. It must be remembered that our experience has been with soils near Philadelphia. Surface drainage we found necessary, owing to the fact that wherever there was a hollow the grass died out. It was not due to winter kill only, but also to excess moisture at other times.
Seed.
Our putting-green mixture consisted of equal parts by weight of Creeping Bent, Rhode Island Bent, and Red Fescue (Chewings, Fescue), which made a very large percentage of bents on account of the smallness of the seed as compared to Fescue, about ten to one. When reseeding our greens, which we have done either once or twice a year, we have used nothing but Creeping Bent, as the Red Fescue did not grow well in our greens. Last year we used Rhode Island Bent* on account of the scarcity of Creeping Bent, due to the war. The fairway mixture on the first course consisted of equal parts by weight of Sheep,s Fescue, Red Fescue (Chewings, Fescue), Slender Fescue, Creeping Bent, and Rhode Island Bent. Here again the bents predominated, but we obtained much better results in the fairways from the fescues, due, we believe, to the fact that the grass is not cut so closely. On our second course we omitted the Slender Fescue, which was of little value to us. The turf on the fairways is very similar to that on the putting-greens, and has given excellent results. It withstands drought, forms a fine mat, and makes little variation in the run of the ball from the fair-green to the putting-green. Our conclusion has been that it pays to buy good, clean seed from a reliable firm, and unless you are given the exact proportions not to buy mixtures. There is a lot of nonsense talked about secret mixtures. There are but few grasses that will form a first-class puttinggreen, and of the two main varieties, fescues and bents, one or the other will probably grow in your soil.
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