Questions regarding repotting hosta

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rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Questions regarding repotting hosta

Post by rufie98 »

I have found some information on repotting hosta but wish I could find more detailed information. If you know of a source of information, please let me know. Maybe you could help me with some questions I have. I know that the right kind of potting media is important. But my questions are:

(1) When can I repot? When is the "best" time to repot? Is there a time when I should NOT be repotting anything?

(2) When repotting, do I remove most of the old media OR is it OK to remove just some of the media, loosen the roots and repot with fresh media? Do most hosta tolerate all of their media being removed or should I expect some decline after doing this?

I am hoping to learn more about successfully growing hosta in pots as I just love those plants!
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Chris_W
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Re: Questions regarding repotting hosta

Post by Chris_W »

Hi,

Regarding #1, you can repot any time from spring to mid/late summer in colder zones (I would say zone 6 and lower/colder). A little later in zone 7, and probably any time in zone 8. The important thing to remember in cold areas is that hostas do not grow roots in the winter and they will rot easily if they aren't root bound in a wet, frozen pot. The more root bound the pot is then the better your survival rate will be.

So #1) If you are in a cold part of the country do not repot in fall.

For #2) I prefer to remove as much of the old media as possible, especially if I need to tease the roots apart to spread them out. Old media typically compacts too much over time and either holds too much moisture or the opposite can prevent good water flow around the roots. Also don't upsize too big, too quickly. Only upsize enough for the pot to become well rooted around the inside of the pot in one season. In the spring I will upsize a little bigger than later in the summer since I like to have full rooted pots before winter.

Media is important in cold areas. Use a good, well-draining, soilless mix for the best results. Soil holds too much moisture in the winter plus causes poor aeration that results in thin, spindly roots that dry out too quickly in drought and don't root out well in the pot. And incorporate a slow release fertilizer, though don't overdo it. We use a 17-5-11 5 to 6 month slow release in our media. You can also use a water soluble fertilizer at a very weak strength each time you water. Something like 1/4 teaspoon per gallon is all you need.

I hope that covers some of it. There is a lot of talk online about people using huge pots and mixing topsoil and compost as media. During a Michigan winter all of my hostas would die in something like that but might work fine in warmer zones like the pacific NW or in parts of Europe.
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rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Re: Questions regarding repotting hosta

Post by rufie98 »

Thanks Chris for some great information!!!!

So, to recap, in Zones 6 or lower, repotting can be done up to mid or late summer. But if one is repotting towards the latter part of the growing season, one needs to repot using a pot that is not too large. The reason for this is that the roots are not growing anymore and will not fill up the pot. If the media gets wet, it will likely stay wet for a long period and the roots will rot.

Seems that removing all the potting media is not a problem---especially if the potting mix has compacted and is not draining well---and the hosta will thank me for it. I need to remember to choose a pot that is not too big as the hosta would prefer to be root bound in a well drained potting mix than be in a larger pot with media remaining wet for extended periods. Also wet media in winter can result in a thinner root system which will not handle periods of drought as well as thick, healthy roots.

In regards to fertilizer, one can add slow release fertilizer to the potting mix or instead one can use a mix of a quarter strength of water soluble fertilizer every time one waters. I see you use a slow release fertilizer in the ratio of approximately 3:1:2. Is this the best ratio for hostas? Is a general purpose fertilizer in the ratio of 1:1:1 good too? If one is repotting mid season or late summer, should the slow release fertilizer still be added to the potting mix (for Zone 6 and colder)?

All the information you have supplied is very helpful to me and I hope to others too. There seems a lot to learn when one begins to ask questions and seek more knowledge. Your advice is invaluable!
Diana
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Location: Northern California

Re: Questions regarding repotting hosta

Post by Diana »

FYI- I have found that if I repot after July here in Zone 9 I get into trouble. That extra soil around the roots with up-potting, remains too moist over winter here where it doesn't freeze. The roots (for me) don't grow into it enough after July, even tho the tops don't die back until late Oct or November. Suspended animation?Just because they remain green during Sept, October and early November, doesn't mean that they are growing roots into the new space. I would save the repotting until spring. IMHO.
-Diana
rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Re: Questions regarding repotting hosta

Post by rufie98 »

Hi Diana. Thanks for your input! Great to hear about your first hand experience! I think then that you agree with one of the points that Chris made---that one should not repot into a larger pot later on in the gardening season. Seems like the media will just remain too wet for too long. But you are also saying that your hostas suffered from being repotted after July (regardless of the size of the pot). Yikes!

I have many pots that are begging for a repot and feel that if I don't get some repotted now, I will have too many to do for next season. My general thought was that if one can divide a hosta successfully (that is in the ground) in the late summer, then maybe one should be able to repot up to about a month before the typical frost date (mid Oct. here). This would allow time for the roots to settle in. I think I will experiment by doing some repotting of just a few of the hostas that have compacted soil. I will repot into a pot that just accommodates the roots. I will make a note of which hostas were repotted and the date so that I can see what happens next year. Wish me luck!
rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Re: Questions regarding repotting hosta

Post by rufie98 »

There is lots of good information here about repotting from Chris and Diana. I am still growing a lot of hosta in pots after all these years. Now that the weather is improving, I have one more question:

Can pots be repotted when the hosta is dormant? What would me the pros and cons of this?
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kHT
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Re: Questions regarding repotting hosta

Post by kHT »

rufie98, just my two cents here. We have learned to let dormant plants alone and not to repot as this to
can awaken them. This we have seen in our early years of doing Brugmansias. We thought we would get an
early jump and found it was not good for the plant. It's about timing and what is good for the plant.
They need their rest in the dormant period.
karma 'Happy Toes' (kHT)
The Goddess is Alive and Magic is Afoot!!!!
I'm just a simple housewife.
rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Re: Questions regarding repotting hosta

Post by rufie98 »

That makes sense kHT! Also, repotting early may mean that the potting media may be too moist for that time of the year. That could mean rotting roots. And I certainly do not need to tend to hosta pots that have emerged early! Even though I do miss them and am excited for the garden to begin to display signs of spring!
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kHT
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Re: Questions regarding repotting hosta

Post by kHT »

rufie98, we purchase soil in the fall as we know the spring stuff is for starting seed soil. Or we wait until we see the
soil being restocked midseason. If we run out I take our clay soil and mix it with the spring soil. We had some really
warm weather in Jan and Feb that made stuff open up early! So the plants here are confused, possible snow will really
sink some of the stuff. Our hostas out back are pushing up and the one in the front barrel is up!!
karma 'Happy Toes' (kHT)
The Goddess is Alive and Magic is Afoot!!!!
I'm just a simple housewife.
rufie98
Posts: 175
Joined: Apr 14, 2012 1:01 am
USDA Zone: 6

Re: Questions regarding repotting hosta

Post by rufie98 »

Good idea kHT---to buy soil/media in the fall or earlier. Sometimes the spring is early and there isn't much available. Spring can be so unpredictable! Wonderful that your hostas are emerging!
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