[Hiseitz]

I have a planter box that is 60” long, 16” wide and 16” deep. It is attached to my deck which is about 7 feet above the ground. I live in west central Wisconsin which is zone 4. Even though I have bought hop plants that say they are hardy in Zone 3 I have never had luck with them wintering over. I want to try digging them up and putting them in my attached garage which normally stays above 20 degrees F. Any suggestions as to what may help their survival. I plant new ones every year and get a decent yield but it gets expensive to buy plants every year. I don’t brew my own beer but have given them away to friends that do. It also makes a good tea. The main reason I put them in is for a privacy screen. I usually put 3 plants in the container. I have tried mulching them but I think the problem is the air gets too cold underneath.  Any thoughts will be greatly appreciated.

[Black Lion Homebrewery]

Treat them like a tender flower bulb (ex, cannas, dahlia, gladiolus).  I'd wait for them to go dormant before digging them out.  I'm not familiar with Wisconsin fall and winter temps, but I'd guess by mid to late November would be fine.  Dig out the crowns.  You won't need to get every root and rhizome just get the main crown.  Let them sit out for a few a week in the open air.  This gives any cuts a chance to callus over.  Then either pack them in cardboard boxes/ plastic crates with saw dust or shredded paper and leave them in the garage. Ideally they stay in a dry (no free water), humid, and cold place. 

Alternatively, if you have extra space in vegetable garden or flower bed, you can dig a trench and bury them in the ground 6-12 inches deep, then mulch them.  I would use a good tag to mark where the plants are.  You can also mulch over top of the crowns to add extra insulation. 

[denny]

Don't do it

[Kevin]

Not a good idea. As hops plants root systems spread out and grow they mature and bear greater and greater yields in the following years. They have spent all summer making great growth strides toward maturation and by digging them up you are taking them back to square one. If you have a variety that works well in your zone they will be perfectly fine just cutting them down just above ground level and maybe adding a bit of straw or mulch. They will pop right up in the spring. Research varieties that grow better in your zone. I live in the middle of Michigan in between zones 4 and 5 and find that Cascade take off like gangbusters while others are slow to get going. Buying new every year or digging them up to try to replant next spring is an exercise in futility in my opinion.

[hopfenundmalz]

His hops are in planter boxes. A pub near me tried to grow hop in planter boxes, made of metal and hanging off the back patio, and none survived a winter of several -14F or more nights. My hops in the ground did just fine, I'm sure the later of snow on top helped.

I'm in SE Michigan. Hops are grown all over the state, but in the ground.

[MNWayne]

If you do dig them up, do not allow the roots to get sun exposure. Sun is bad for roots.   Is there any way to plant them in boxes on the ground?  How tall is this deck off the ground?   Hops can grow very tall.  On the ground and covered in mulch, your zone 3 hops will survive a zone 3 winter.  Elevated boxes just won't work and bringing them in each fall means you will always have 1st year plants.

[goose]

I agree, I would not dig them up.   If you can move the entire planter box into your garage, your hops should winter OK.  Planting them in the ground is the better idea if you can do it.  Leaving the boxes outside with the rhizomes in them exposes them to too much frigid air surface area around the rhizomes which is why they die on you.