Your picture "master Gardener couldn't figure out" Is environmental stress. Likely heat, possibly added hot sun.

The heat plus sun (on the plants and the pots) on your south exposure could also explain the collapse of some plants. Or not.

As for the collapsed strawberries, here's some homework:
1. Sacrifice one of the failing plants to a "lab test"
2. Dig it up
3. then look at the roots -- healthy roots should be creamy.
4. if dark and/or black on the surface, it's a root rot.
5. then lightly grasp a root between two fingers and try to slide the covering off. The core is likely to remain. If so, yep, it's root rot. Could be excess water or other things.
6. Then cut vertically down through the center of the plant. Any discoloration? If yes, what? If any redness, it's red steele -- a crown and root rot.

If it's red steele, the plants were contaminated by infested soil somewhere along the line.

And if so, discard the potting mix, wash the container with soapy water and rinse well before re-using.

Hi Jean,

Thanks...

Ok, results: I pulled up one of the plants and saw creamy roots on top, darker as they progressed downwards. The root covering was able to be pulled off from the very bottom (about the last 3/4 inch), so I assume they are going through root rot- interesting- I always let it dry out before watering and water always drains through as I'm watering, so I don't think the drain holes are clogged or anything. Hmm... Anyhow, if there is just damage to the bottom parts of the plant's roots, can it still be saved by trimming the roots back to the healthy area and repotting in a different soil? (I'm assuming the soil needs to be ammended/changed to make it more well-drained if the culprit indeed is root rot).

Also, since I used brand-new store bought potting mix for this container of strawberries, would there still be a chance that the soil could be infested (since they are in containers and nowhere near the ground- 3 stories up)?

Thanks for the help.

Here is a link that might be useful: Lots of pictures of the problem...

Sorry- the reason I'm asking the last question is because I feel terrible cutting up the little plant since a lot of his roots still look healthy.

Sorry about your little plant. But it's easier to proceed once you have an accurate diagnosis. Without an analysis of the victim, everyone is guessing what's happening.

The really bad news is that if the tips are rotted, there's no way of stopping it from extending further.

You can try to remove just the affected plants, then wait to see if the others are okay. Only time will tell if you will lose all of them.

I know that's probably disheartening to hear but that's the way of gardening -- learn by doing.

Potting soil is clean when originally packaged. But it can become infested if stored on contaminated ground anywhere along the way to your place, and even at your place.

Another method is when the gardener mixes garden soil into the potting mix "to make it better."

Then too, one must consider the plants. Typically they also start out clean. Even so, they may become contaminated along the way.

Thanks, Jean.

They are all going now. =(. I don't have any soil to speak of here (live in a tiny apt. on the third floor) so I am guessing any contamination had to have come from the potting mix that I used and/or the vendors along the way. It's just so strange how they declined SO rapidly- had a great rebound, and then the next morning, almost entirely wiped out.

Is there any way to avoid this next time? Is there a better soil mix, for example? Obviously, I will discard all the soil in that pot (unless you think I could use it for another plant which is not affected by this?). I would still like to try to grow strawberries in the future, but I want to learn how to correct this. The resources online don't really cater to container gardeners who have problems with their strawberries.

Well, as I said, either the potting mix or the plants were contaminated somewhere along the way.

As far contaminated soil goes, it may have been as simple as the bagged potting mix on wet soil, or the same with plants (whether bare root or potted).

Further, this may be your one and only nasty experience with such problems. Put simply: it happens.

You still have time to start over this season with something else.

Then next year, try strawberries again.

Lift up your pots. If they feel light, the soil is dry!! Take the pot and set in the kitchen sink and fill with water. The pot will float until the soil become saturated. Drain the pot and proceed to the next one. Do this once a week to make sure the soil is saturated and your plants will respond with strawberry galore. Remember me when you eat the first one.

When you plant strawberries again stir a handful of grocery store cornmeal in each planting hole and also spread it on soil surface beneath plants. Every second week toss more cornmeal under the plants. Keep the soil evenly moist. This should prevent strawberry crown rot.

Unfortunately, the root rot probably came from the grower, not from anything you did or didn't do. It's not uncommon for strawberry fields to experience high loss if they become infected and the starter plants can be sold off before the infection is obvious.

If you still have the plants, take one to your extension agent and ask that it be sent for diagnosis by your state university. It's possible that the grower might make good your cost of these plants if they had a crop loss and you can prove where you bought them.

Sterilize the pots before growing anything else in them by soaking in 1 part bleach to 9 parts water. The pathogen is fairly tough and could possibly contaminate whatever you plant in them in the future.

Sorry the Master Gardener didn't get a diagnosis for you. In VA we're trained to do whatever is necessary to find the problem, including sending plants off for lab tests at VA Tech if we can't figure it out. If you were not offered this service, you might mention it to the agent if you talk to him or her.

Check the link below to an article on the subject by Utah State University.

Here is a link that might be useful: Black root rot article

As I said earlier, contamintion at the grower is just one place the plants can acquire problems.

Beyond that, it would be very difficult to determine the source of the contamination at this time.

Not "contamination"....it appears very clear to me that they are not getting enough water, either because they are and have been allowed to dry out ro because they were over watered and the roots rotted from soggy soil. Is there water standing in the saucers of those pots?
If it were black root rot they would not have appeared as healthy plants in the morning and limp wilted sick things that same afternoon.
Linda C

Forget the conspiracy ideas. The problem is the lower part of soil in the pot IS NOT moist, thus the dead roots and surface roots are healthy. Water you pots as I outlined above in this string.

The pots I have are sort of connected to their saucers- it's a large pot (14 gal, I think). The guy in the garden area told me to get it that large, but I am thinking it might be too deep? The soil never feels dry. I only allow it to get dry to about the top inch or so, still moist underneath as per instructions I've read online. I always then water til the water runs through the pot. The only way I can tell it is running through is because the saucer starts to overflow- I can't physically see the saucer starting to fill (if that makes sense- because the saucer and the pot look like one unit- flushed walls). The strawberry roots do not reach all the way to the bottom of the pot.

One note. Soil has more open space than solids per unit of volume, so water running through is like water through a fine sieve. I always moisten potting soil as the pot is being filled. This increases the water holding capacity of the soil because of the physical nature of water. Simply put water clings to water. If you want a further explanation, let me know.

Yes, please. I am not sure I understand what you are trying to say. Do you mean as you are filling the pot with soil, initially (as you are transplanting)?