dragon wing begonia - over water? sun damage?

Question: I got 2 Dragon Wing Begonias on May 1st.  I know nothing about gardening and the most I have done is water them.  They are planted in huge pots, (26"x13") that are completely filled with potting soil, so drainage should be good.  I bought a "XLUX Long Probe Deep Use Soil Moisture Meter, Water Monitor Indicator Sensor, Hygrometer for Outdoor Indoor Large Pot Plants, Flower, Gardening, Farming" on Amazon and when I stick that in the soil is shows green. They get some full sun, but I guess less than 1/2 the day.I don't think mine look much like https://ask2.extension.org/kb/faq.php?id=659682, but again noob here.

responder: The Question Asker Replied July 25, 2024, 5:23 PM EDT
response: In case it matters - after the deer snacked on the begonia I have applied "Liquid Fence Deer & Rabbit Repellent" a few times.

responder: PA Virginia Replied July 29, 2024, 3:51 PM EDT
response: Rhonda:  Thanks for your question.  From your photographs your plants appear to be suffering from overwatering, so please let them dry out for awhile.   While water meters can be useful, they are not precision instruments. They are most useful for letting you know if the bottom of the pot is wet or dry.  Plants need a certain amount of drying out to allow air to penetrate the soil.  Do your pots have drainage holes and do they also have saucers? If so, does water accumulate in the saucers for any length of time after you water? It would help me to better understand your situation and how best to remedy it if you would also send some photos of the plants as a whole. I want to see the relative sizes of the pots and the plants.  Thanks.

responder: The Question Asker Replied July 29, 2024, 6:30 PM EDT
response: I have stopped watering.  I bought the planters and a landscape service planted the begonia.  They filled the entire planter with potting soil. Today, I tipped one planter over and stuck the water meter up one of the small drainage holes .. it measured off the chart wet. So .. um .. yes .. probably swimming down there.  Maybe that planter should have bigger drainage holes or not be filled entirely.  The reason the begonia is over watered, has nothing to do with the begonia and everything to do with me. On the other side of the property they moved/replanted an ailing magnolia. I forgot to water it, or maybe it was going to die anyway. Any-hoo in an attempt to not let the begonia die, I made sure to water it, regularly.  I probably would do fine if I believed/trusted the water meter.  I work best if I can measure the result, that's why I bought the meter. Take the guess work out if.  I was given this instruction  "Stick your finger into the begonia pots as deep as you can. If the finger has soil sticking to it or you feel the soil is actually wet – don’t water. If your finger comes out dry or with dry particles of soil clinging to it, then water."  If I stick my finger in the pot it does not feel wet (the pot is huge) and there are dry particles clinging to my finger .. so that (unlike the meter that penetrates deeper and reads moist) did not make it clear that no water was needed.  What to do now?

responder: The Question Asker Replied July 29, 2024, 6:40 PM EDT
response: drainage holes from the actual planter - which is easier to see. and today's sick leaves I have pinched off (to the notch below the leaf) handfuls of dead leaves.

responder: PA Virginia Replied July 30, 2024, 10:14 AM EDT
response: Rhonda:  Thanks for the new pictures.  That helps a lot.  First, your begonias don't look all that bad.  Not watering now is a good first step.  Second, put down something to catch the soil, then carefully put the container on its side and very gentle take the begonia and root ball out.  Try to keep the root ball intact.  Then look at the roots, gently prying them apart if necessary.  They should be whitish brown and somewhat crisp, not black and slimy.  Then smell it.  It should smell like fresh earth, not like a sewer.  Put the plant right side up, not in the container, to dry out a bit, and let me know your observations.  Also, check the soil left in the container.  Take it out and put in a separate pile.  Whether it can be reused depends on what it smells like.  If like a sewer, discard and get new soil if necessary.  Also, how heavy are the pots?  Let me know if they wouldn't likely tip over when empty.  You really don't need the whole pot filled with soil.  You can put other things (small flower pots, bricks, stones, etc.) in the bottom to provide weight, take up some space, and also provide a reservoir below the roots for any excess water that might accumulate. Protect everything from any rain.  By the way, where are you located? Do you know your hardiness zone?

responder: The Question Asker Replied July 30, 2024, 8:23 PM EDT
response: I just noticed the ad says the "planter shelf" can be used either as a bottom tray (as I have it) OR a soil saver. So that is something I can try. The pots are quite light, I would be worried about making them top heavy. Hardiness zone image attached.

responder: PA Virginia Replied July 31, 2024, 9:08 AM EDT
response: rhonda:  The idea of putting heavy things (clay pots, bricks, stones, etc.)  into the bottom of the planter is to weigh it down so it doesn't tip over in addition to reducing soil usage.  Another thing to consider is to put the begonia in a separate pot that fits into the top of the planter.  That way you can remove the plant without moving or disturbing the planter.  As you live in zone 7a and your begonia will not survive the winter outdoors, having it in a pot makes it a lot easier to overwinter in an unheated garage or basement if you choose.  How is the root examination going?

responder: The Question Asker Replied August 03, 2024, 10:50 AM EDT
response: Ah winter. Did not think that far.  Each large pot has 4 separate plants in, so getting them out in one group was quite the challenge. I only did one container.  I did not notice anything smelling and if i try and smell the dirt, it just smells like wet dirt. The roots are were very fine and don't appear slimy. (picture attached) I found one 2 inch piece of root that looked like it broke off as I wrestled the plant out and it looked fine. Not slimy but brown and firm.  I tipped all the dirt out and had to improvise somewhere to put it. I don't have any undercover, so I put up the sun umbrella. This is not a long term solution.  I looked at where the "soil saver" fit in the pot and am unsure about what next. The point about winter is well taken. I have a shed but no garage. It may be possible to wheel the whole big flower pot over to the shed for winter. I don't know if I could get the 4 plant root ball into a smaller pot that would still fit into the big one.

responder: The Question Asker Replied August 03, 2024, 10:59 AM EDT
response: Picture showing where the soil saver sits in the big pot. Picture of the taken-out plant  now. And a picture of when I first threw out the dirt.  It's definitely very wet dirt. How would I judge that it is dried out enough?

responder: PA Virginia Replied August 03, 2024, 12:49 PM EDT
response: Rhonda:  Thanks for the info.  It sounds like you caught this in time.  If the soil doesn't have an off odor, it is probably okay to reuse.  Let it dry out a bit.  One test for when it is okay is to make a ball (like a snow ball).  It should hold together, but not be sopping, and you should be able to gently break it apart with gentle pressure.  The soil should look and feel like a good chocolate layer cake - moist but crumbly.  It won't crumble if it is still too wet.  It looks like the soil saver was designed to do essentially what I suggested with the pots, rocks or stone - fill up the container so you don't need as much soil.  It looks like there is still a bit of room around the plate structure.  You might want to put something like small stones in these spaces to provide additional weight so the container doesn't tip over.  Then replace the plant and soil after they have both dried out.  I still think putting the plant in a pot to fit inside the planter is an easier way to go rather than to move the whole planter (unless the planter itself is not frost-proof, in which case it needs to be put somewhere for the winter where it won't freeze as well). As to a pot, the opening appears to be square, so if you get a round pot with a diameter at the top a little less than the length of a top side of the planter, and the diameter of the bottom a little less that planter side as it slopes, it should fit. You may need to get a few measurements of the inside to make sure.  Although this may seem like a lot of work now, it should make things a lot easier later on.  You may need to add some material on top of the soil saver to get the right height.  This approach would make over-wintering both the plant and the planter easier to manage.  By the way, you can remove some soil from the root ball to get it to fit.  It doesn't look as though your plant is anywhere near filling the whole root ball.  Gentle root shearing can also stimulate more compact root growth.  In the future, wait until the water meter shows the bottom of the root ball is dry before watering, and then add the water a bit at a time until it registers just wet.  Make a note of how much water you added as a guide to the future.  Now that you know about overwatering, you should be able to avoid it.  One more thing, if you would like to have a phone conversation to discuss all this, please send a phone number and some convenient times to <personal data hidden> and I will set up a time to call you.    This is a private Penn State Garden Hotline email, as opposed to this more public one.  I support that Hotline as well, so if you mention me (Virginia) in your email I will get it.  Please let me know if you have any questions or concerns.

responder: The Question Asker Replied August 03, 2024, 2:43 PM EDT
response: I went out and bought two pots and some rock/stone for weight in the bottom. I took the big pot with me and this was the best fit. It's sitting on the soil saver and reaches the top nicely.  I broke the one big clump into 4 pieces. They are still too big to fit in the one round pot, as-is, but I probably make it happen, unless you think it is too much plant(s) for one round pot.  I made a dirt ball with the sun-drying dirt and I can form a ball and if you touch is it falls apart...

responder: The Question Asker Replied August 03, 2024, 2:49 PM EDT
response: If I use the soil saver I have way more dirt than I need. Weather is calling for thunderstorms at 5pm so best case scenario - I force-fit the 4 plants into the round pot, using what soil is needed and put the left over soil in a bag in the shed. And then do it all again tomorrow for the other container.  I drilled more holes in the soil saver, and then the round pot. Also removed the round pot's attached saucer. Should I put the round pot into the square pot with or without the saucer attached?

responder: The Question Asker Replied August 03, 2024, 5:26 PM EDT
response: it's 5pm and it's done .. or a version anyway ! I force-fit all 4 plants in.  I had approx 3 inches of soil on the bottom of the round pot before I put the plants in.  The round pot is sitting lower, about 2 inches below square pot edge, now that it has some weight.   With the rain coming, I forgot to put stone in the bottom of the square pot. But as you say, very easy to take the flower pot out now, so easy fix later.   I put the round pot in without it's saucer.  I added a little more soil between the plants where possible. Was not much. I have two more bags of potting soil in the shed now. Does potting soil keep indefinitely?  I hope so! After all the potting, I put the probe in all the way to the bottom of the round pot. (  That is easy to find, not sure how I would find the bottom of the root ball. ) Probe read moist, in the middle of the green. It read that at shallower depth also. If I put the probe in very shallow, maybe finger depth or less, is shows red / dry. Let me know, I can do it differently, plants allowing. :)

responder: The Question Asker Replied August 03, 2024, 5:28 PM EDT
response: Based on the probe I did not water the round pot at all.  it's going to be rained on later :)

responder: The Question Asker Replied August 04, 2024, 12:32 PM EDT
response: Today's weather and my time is not allowing for the other pot to be done today.  It may have to wait for next Saturday. I will simply not water it.  If the bottom of the container is wet and I don't water the plant in the top, can the plant pull up water from the bottom of the big container?  I sent email to the other email address.

responder: PA Virginia Replied August 05, 2024, 1:47 PM EDT
response: Rhonda:  What you did appears to be fine. You put the round pot into the square one, without the saucer.  While saucers can be useful, unless they are emptied promptly they can lead to root rot issues as well.  Better to have the open space beneath the pot for any excess water to stay below the soil level.  One issue - are the plants in the pot root bound?  This means that the roots have really taken over the soil in the pot and you can see them all over the bottom and sides of the root ball.  When this happens you need to repot into a larger container.  In your case, you would probably be able to just use 3 plants rather than four.  That would leave you an extra plant from each container that you could then plant together in another pot.  From the pictures you sent it didn't look as though this is an issue.  Potting soil can last a long time if it doesn't get and stay wet.  If wet it can develop fungus that could harm any plants you use it with.  If it does get wet, but you get to it quickly and spread it out to dry, it may be all right.  Give it the smell test.  As a reality check, while we are trying to do what we can to save your plants, it is possible that they won't recover.  Only time will tell.  In that case, you just chalk it up to experience and vow to do better next time.  This sort of things happens to all gardeners from time to time.

responder: The Question Asker Replied August 05, 2024, 9:50 PM EDT
response: As seen in pictures     ge_IMG_1971.JPG      ge_IMG_1971.JPG      When I broke apart the 4 plants there were fine roots all through the dirt. No defined shape as I imagine root bound to be. I had to  "shear off"  quite a bit of dirt and roots to fit the four plants into the round pot.   There was very little space left to fill in with dirt.  If I put two plants in a separate pot, what size pot? May as well get the right size. I have the dirt  I understand the plants may still die, but I feel better making an informed attempt.   When I belatedly tried to save the Magnolia, I bought some miracle grow. That is on hand if useful.

responder: PA Virginia Replied August 06, 2024, 11:05 AM EDT
response: Rhonda:  When potting a plant, you want to pick a pot that is about 1 inch in diameter larger than the diameter of the root ball.   So, if the root ball is 4 inches across, you want a 5-inch pot.  For two plants use the sum.    When repotting, when a plant is pot-bound again you want a pot that is one inch more in diameter.  Slightly larger is okay, but you don't want too big a pot.  The pot needs to match the root size because too big a pot will hold more soil and stay wetter than desired since there are not enough roots to soak up the water.  So, you repot in successively larger pots are the plants grow.  As an alternative, you can divide or split the plant as I suggested you do.  That way you can get about the right balance.  I have attached a Fact Sheet that can provide additional information.   Is 6:00 pm this evening a good time to call you?  I want to discuss your groundcover issue.   Regards,   Virginia Cunningham   Master Gardener, Garden Hotline   Montgomery County 1015 Bridge Road, Suite H, Collegeville, PA 19426 Phone:<personal data hidden> e-mail: <personal data hidden>      Please take a minute to participate in our survey at   https://pennstate.qualtrics.com/jfe/form/SV_2mMPoSNfLF6umd8  To receive the latest home gardening news and events, sign up for our newsletter (to the left under Get Connected) here: https://extension.psu.edu/trees-lawns-and-landscaping/home-gardening           From: ask=<personal data hidden> <ask=<personal data hidden>> on behalf of Ask Extension <<personal data hidden>> Sent: Monday, August 5, 2024 9:50 PM To: Cunningham, Virginia L <<personal data hidden>> Subject: New response added to your question (#0148587)

responder: The Question Asker Replied August 06, 2024, 4:26 PM EDT
response: 6pm is good.