Poa Cores, of course!

Greg Evansin Golf

Picture 1. 25 trees to be cleared
When Ealing Golf Club decided they wanted a chipping green on a bit of scrubland, it was left to Course Manager Greg Evans to come up with a plan. Given that the time frame was just fourteen weeks - and at the beginning of the playing season - what was his modus operandi? Poa cores, of course!

Last April, our club decided to construct a chipping green on a bit of scrubland by the 11th century church at Ealing Golf Club.

They had been considering a chipping green for a number of years, but the lack of a suitable site was always an issue. As we were about to head into the golfing season the timing wasn't perfect, but I'd been pushing for one for several years, so I wasn't about to say no. Initially, I was excited, but then reality set in. The club wanted the green in play that season, but there were twenty-five trees standing in the way for a start, and no materials or suppliers had been sourced. It was going to be a busy spring!

Picture 2. Area cleared in 2 days
My thoughts turned to how the green would play in terms of quality and performance. Ealing's greens are classed as old 'clay based push ups', with many over a hundred years old. They were designed to 'hold water'; as it was pre-irrigation days, keeping them alive in the summer was the main focus. If we added a brand new full USGA specification green, it would be completely alien to the other greens on the course and stand out like a sore thumb. However, it would be irresponsible to build a new green identical to the 100-year-old ones. We needed a design that would allow the greens to play as closely as possible to the main greens without compromising their drainage capabilities.

In the past, I have designed greens that were along the USGA lines, but tweaked things such as shallow rootzone levels to perch the water table a bit higher and give the green a slightly 'softer' feel compared to full USGA guidelines. These worked well, allowing the new green to sit quite comfortably with older greens.

Picture 3. External soil brought in
Another issue was the type of grass species to be used. I have always joked that the greens at Ealing are 99% Poa with a token 1% bent. The reality is actually not too far from that. Our site is clay-based parkland and Poa annua thrives in the wet, dark conditions. The new area for the chipping green was in a very shaded site, so it made sense to go with Poa there too. The challenge was to recreate the Poa sward without turf or suitable seed being available on the market.

Time frame provided our final obstacle. It was decided that the project would run from spring to the autumn meeting. With a start date of the 12th May, we would have until the 6th September before it needed to be performing at championship standard - just fourteen weeks for tree clearing, construction and grow in. As we were approaching the playing season, I felt that this was achievable.

The Design Process

As the club wanted a quick turnaround, we had to get started quickly. My role was to project manage, with Ricky Willison (our Director of Golf) designing the green and Weller Design providing architect drawings. The project was due to start after the spring meeting on the 3rd May, leaving four weeks to source and test materials. We chose European Turfgrass Laboratories Ltd (ETL) up in Scotland as our testing site.

Picture 4. Gravel carpet laid
Ideally, the green should look and play as closely as possible to the other nineteen greens at Ealing (including the putting green) with the same grass species. It didn't have to play to the standard of a USGA spec green, but must handle extreme wet weather; an increasing issue in the UK. As we would have around a twelve week growing in period, turf would be the easy option but, in my opinion, not a suitable one. Turf would look good on day one but, within weeks, you could go backwards. With the club expecting a top class green, I did not want to take the risk.

Seed was another option that was not really viable. If we went with the traditional fescue/bent, it would not produce the required standard within the time frame. Creeping bent was definitely an option as it is a fast germinator and would produce the required standard, but it is a different species to the other greens on the course.

Two solutions countered these issues. First, a shallower rootzone than the 300mm standard used in USGA designs. A gravel layer would be added along with drainage, but the rootzone would sit at 250mm deep instead of 300mm. This is something that I had done before on previous projects, which not only saves money in time and resources, but also allows the rootzone more moisture. Perfect for Poa!

Picture 5. Main greens being cored
Second, cores. Over the years, I have implemented turf nurseries and made several tweaks on existing greens using Poa cores instead of imported seed or turf. These worked extremely well. However, I had never created a full green with this method. What I had seen was how well Poa cores had done in terms of germination and performance. The other great advantage was that a Poa cored green would look exactly the same as other greens already on the course.

So, with the rootzone depth set (and tested by ETL) and the Poa core method confirmed, we were ready to go!


As the golf season would be in full swing, we decided to use some external labour for the construction and site clearing. I'm usually really keen for clubs to do construction jobs in house but, without that option available, we selected people that we've worked with before; people that I know do the work to my standard.

Work started on the 19th May. The first task was to fell all the trees, which was done within two days by our external tree surgeons, Moore Trees. As soon as the last tree came down, some external spoil was brought in to create the green's shape.

Once all the spoil was laid, Oliver Flanagan (who has worked with me on other projects in the UK) did the grading and shaping. It was decided that the grass surrounds should be to the same standard as the green itself, so irrigation and drainage pipes would be installed and a 50mm 'sand carpet' would be laid in this area to help with performance.

We were now two weeks into the project. Our main aim was to get the green finished as early as possible, so that we would have an extended time for the grow-in, which would be tight anyway.

Picture 6. Cores being added to the green
On closing at the end of week two, we had the trees felled, green shaped, materials added and irrigation and drainage laid. We were ready to lay cores on the 2nd June.

Core laying

As the new green would be 300m2 in size, we knew that we would have to use the main greens as the source for the cores. We were now officially into the playing season, with societies booked and competitions in play, so it was far from ideal. But the club wanted this green playable as soon as possible, so there was no other option.

My first estimate was that we would need three or four greens for the cores. That seemed manageable in terms of returning the course back to standard very quickly. However, it quickly became apparent that we would need to use rather more greens. In total, eight greens had to be hollow cored, each needing a recovery plan afterwards. The membership weren't entirely happy about it, but the additional facility was worth it in the end!

Picture 7. At the end of a long day, green given a roll

To get the cores, we set our verti-corer with 12mm tines going down 50mm deep on a 50mm square pattern. We started laying the cores on the 2nd June and, as I was keen to do it in one day, it required a big effort by the greens staff.

The cores were laid out around 25mm thick. They were spread evenly across the green and raked out. Once laid, I decided to apply creeping bent A4 seed set at 2g/m2 as back-up, just in case the Poa didn't take the way I wanted it to. I need not have worried!

At the end of that first day, the cores were down and seed sown. To finish it off, we gave it two rolls with a hand mower, using just the metal roller at the back. It looked pretty good after that!

Grow in

All the hard work was now done and the project entered the grow-in phase. Anyone who has experienced a grow-in will tell you that it can be just as intense as construction - and as important. From my experience, the importance of the grow-in is often underestimated; it is common not to have any budget for it at all! The grow-in can make or break a project and should be planned for in the same way as the design and construction.

The focus for the first few weeks was on feed, water and dressing. We had twelve weeks left to get the green up to championship standard.

Picture 8. Within days the green had a green tinge

One of our seasonal assistants, Wes Lenihan, was given the opportunity of supervising the grow-in. With labour tight, Wes put in many additional hours and I'm sure that the end product would not have been to the same quality without his work.

Our first target for the green was to create density. However, we immediately found that the Poa did germinate, but didn't do much else. It sort of just stood there for a few weeks in a 'Bonsai' sort of state. The bentgrass came through very quickly, but didn't stay around for very long once the Poa woke up!

To give you a clearer picture of the grow-in, here is the programme we followed for the first eight weeks:

- Heavy hand dressings with pure sand every Monday, Wednesday and Friday to help dilute the thatch layer (which comes with Poa cores), firm the top surface and even it out

- Feeding programme - a combination of granular and foliar, starting with granular (ammonia/sulphate), followed by foliar the following week, then back to granular. These bounced off one another for that period

- Greens rolled before sand dressing for the first few weeks. After two weeks, it had the first cut, using a Toro Flex 21 set at 6mm with no boxes. Once grass coverage was attained, it was cut before every sand dressing (three times a week)

Picture 9. Wes at work giving the green a heavy dressing

- Intense watering to begin with, using a Rainbird valving-head system, the same as on our other greens. To start with, they were set on a four hour cycle with 2mm of water applied each time. It then decreased to a six hour cycle after the first week, reducing further to a more traditional approach once we were cutting regularly

No seed heads!

The most interesting thing I discovered was that, once the cores went down, we had zero seed heads. When we laid the cores I expected, and actually wanted, a flush of seed heads as I felt it would improve density. It didn't happen and I can't really explain why. Perhaps, because it was watered and fed well, it was happy and content. Poa tends not to seed if it is happy.

Final grow-in and opening

At around the eight-week grow-in stage, with four weeks to go before opening, we started to ease off on the intensity of the feeding, watering and dressing programmes and change our mindset from growing to maintenance.

Picture 10. Putting surface after 6 weeks

Until that time, it had been about germination and gaining a surface. Top growth was required. But, as we headed into the final period, we wanted to control growth so that the green would be suitable for play. A lean, mean sward was needed!

With this in mind, we ceased granular applications, but increased the foliar applications to weekly. We wanted to really control the growth in the final stages. Interestingly, at this stage, we included the growth suppressant trinexapac-ethyl with the programme, but quickly removed it as it seemed to knock back the top growth slightly.

Heavy hand dressings were replaced with lighter, more frequent ones. We found that using a drop spreader with kiln-dried sand in 25 kilo bags worked very well. 150 kilos per application was a perfect spread for us and was applied three times a week.

Cutting regimes also increased and the height of cut came down from 6mm in week one to 3mm by week ten. We had to be careful, as the green design is very undulating to give it some character and challenge needed for a chipping green. With the interesting slopes on the green, we found the Flex 21 with floating heads worked very well.

Picture 11. Opening day 10 weeks after construction

Finally, the irrigation was reduced dramatically. From approximately 10mm a day of water in week one, we were down to 1 or 2mm at night if our moisture meter said it was required. We set the volumetric water content at 20% for this green (10% lower than our clay based ones). Anything under would require an application of water through the sprinkler system.

As we headed in to the final phase, everything looked great and the green was performing to the required standard.


From the first conversation with the Course Director in April to the finished product in September, everything worked out really well on this green. Everyone involved put in a huge effort. The Poa cores had a slow start but, once they got going, their performance far exceeded my expectations.

The original plan was for the green to open for play in September and October, but shut for the winter to give it a rest and allow maturity. However, as we headed into November, it looked great and we have kept it open all winter so far. With the area being very shady, I don't think there is any other grass that could handle this sort of intensity and pressure.

Picture 12. The area has been much improved
Creating a top quality green or adding to an existing green is always hard. For each situation, many factors will dictate what goes down. I feel that this method has a place and, if you require an instant Poa surface, laying down cores is certainly an option. The great thing is that it's cheap as no turf or seed is required and, if you give it some fuel (feed and water), it will be off and running.

Greg Evans MG is Course Manager at Ealing Golf Club and runs an Agronomy business, advising clubs across the UK and Ireland. He can be contacted via his website www.gregevansmg.com or by phone on 07951 157208