Thinning strawberry crowns

I have 50 sparkle strawberry plants in a hill system spaced 12 inches apart in holes cut through weed block fabric. I planted them last year and picked off the flowers and cut the runners off. They are producing nicely this year but I'm already thinking about renovation.

I plan to mow the plants an inch or two above the crown and then have read that I should thin any crowns with five or more branch crowns.

Does anyone have any experience thinning strawberry crowns that they can share? Is it difficult? Do I cut out and remove the middle crown? Or just cut out and remove half the crown?

Any suggestions on how to do this without harming the plant would be appreciated.

More broadly, is this crown thinning really needed?

Thx

I'm not sure what is meant by "thinning the crowns." All I did with mine was to clip off all but the strongest looking runner produced from the mother plant. I then pegged that runner into the ground in a row across from the mother plant so it could grow into my next producing plant. When the original plant begins to wane in it's production of strawberries, dig it out and throw it away and, by that time, the new plant should be ready to produce. Repeat this procedure each year.

Thanks for the suggestion!

By thinning of the crowns, I meant removing a portion of the mother plant, leaving a smaller mother plant. It's what the pros do when they carry forward strawberries in the Hill system for a second year. See http://pubs.ext.vt.edu/438/438-018/438-018_pdf.pdf , though they use chemicals to kill half the plant. The purpose is to improve berry size by reducing the number of strawberries that get produced. Apparently, multiple branch crowns form on a strawberry and if you carry forward all the branch crowns, the strawberries are too crowded.

It's the same principle as dividing any other perennial, except that I plan to leave half the crowns in the ground to bear for the next year. Presumably, they will form new branch crowns so the plant size next year should be about the same.

I might try an experiment and use the method you suggest on a portion of my bed. Then we'll see which method produces the best berries for the least work.

This article suggests cutting crowns with 5 or more branches in half with an asparagus knife, which is what I'll try: http://www.grapesandfruit.umd.edu/Strawberries/StrawberryPlasticultureManuscript.pdf

I hope to check back next year with results!

Thanks--I'm bookmarking the sites you included. I'd love to know the results of your experiment. It's been many years since I had a strawberry bed because we lived in a subdivision. We now live in the country and I have plenty of room so I plan to put in a strawberry bed next spring. My method is what was used by everyone I knew back then but it's very possible they've come up with better methods now and I'm more than willing to give them a try. This year I started 10 blueberry bushes. I removed all the berries but missed one which I found when it was mature and gosh was it sweet! I'm really enjoying having all this room to grow things. Hope your strawberries do real well for you.

I've just completed thinning the crowns, so thought I would update the post. Turns out it is incredibly easy -- just inspect the crown to see if it is too large and then slice straight down with a steak knife where you want to divide it and pull out the part you want to remove with your hands. I generally tried to leave 2 or 3 crown branches at most per plant. I left plants that were still small alone and didn't thin them.

It was so easy in fact that I didn't end up doing the experiment I planned to compare yields against a field propogated by one runner per plant, as Naturelover1950 suggested. Sorry! It would have been too much work.

But I did dig up some other references to maintaining strawberries in the Hill system for multiple years, which I've reprinted below in case anyone else is trying to find this material. In brief, it appears that so long as you properly renovate the planting (cut off all foliage and thin the crowns), a planting using the Hill system should produce well for three years. In fact, yields go up in year 2, though berry size declines a bit. The trial described in the first link documented yields, berry size, and # of runners in the first and second year of production for a number of different varieties. (Note: in the trial, they thinned the crowns in the fall, rather than spring. I thinned in spring as suggested in other sources. Not sure of the impact.)

http://ag.udel.edu/extension/IPM/MAVWReports2009/NewellStrawberryVarietyTrial.pdf
http://pubs.ext.vt.edu/2906/2906-1320/2906-1320.html
http://chestofbooks.com/gardening-horticulture/Journal-14/Results-Of-Strawberry-Culture-By-Rows-Or-Hills.html

One final caveat -- I am clearly in the minority in trying the hill system at home for june-bearing strawberries. Almost everyone seems to use the matted row method. I like the hill system because it produces larger berries and allows me to put down a thick fabric mulch that virtually eliminates the need to weed. It does mean I need to cut off runners, however, which can be a bit of a pain. But the fabric mulch makes it easier since they have trouble rooting.

I will try to report back after next year with info on how well the renovated planting did.