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I planted some morning glory vines (Ipomea sp.) outdoors in a box about 10 weeks ago (mid-March, I'm in Zone 8) and they've been underperforming the whole time -- the vines are not even a meter long, and many of the new leaves have been small, pale, and twisted, while the older leaves are irregularly-discolored and sort of raggedy-looking.

morning glory leaf 1 morning glory leaf 2 morning glory leaf 3 morning glory leaf 4 morning glory leaf 5 morning glory leaf 6

Their planter contains a loose, acidic, slightly sandy topsoil, to which I've added a variety of liquid fertilizers over the past several weeks (see below) in a largely unsuccessful attempt to remedy these symptoms The vines receive about 7-8 hours of full sun per day, and get watered regularly.

The morning glories share the planter with some of the most exuberantly healthy-looking nasturtiums I've ever seen, which suggests that these conditions are not generally inhospitable to plant life.

I suspected some kind of nutrient deficiency (though nothing in particular quite seemed to fit the symptoms) and at roughly weekly intervals I have tried liberally fertilizing with one of the following:

  • Miracle-Gro (12-4-8)
  • Epsom salt solution
  • Chelated iron
  • Calcium phosphate suspension

So I'm assuming the plants aren't deficient in N, P, K, S, Ca, Mg, or Fe, at least.

Sadly, none of the above seems to have helped much. If I had over-fertilized the container, I might expect to see some problems with the nasturtiums, but those just keep accelerating. Moreover, the slow growth and pale-twisted leaves on the morning glories preceded the addition of any liquid fertilizers.

Does this look like some kind of disease? A virus, maybe? I don't see any pests on the vines, with the possible exception of an occasional red mite. I have a microscope, in case examining the leaf tissue at higher magnification could be diagnostic. I'd appreciate any suggestions, I'm running out of ideas.

UPDATE: Found some aphids hiding down by the dirt in the lowest leaves of the morning glories. Maybe they came for the nasturtiums and stayed for the morning glories? The worst-affected leaves are not the ones that currently have aphids on them though, and I've never seen aphids on the upper leaves.

UPDATE 2: Grabbed this little bugger off one the worst-affected leaves -- looks like a thrip. Maybe that's my problem.

thrip

user1870614
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    what is the size of the container - height, width and depth? – Bamboo Jun 03 '16 at 11:25
  • what's on the underside of the leaves? – kevinskio Jun 03 '16 at 11:48
  • @Bamboo, the soil height is 18 cm, and the box is 150 cm wide x 23 cm deep (7" x 5' x 9"). There are about 10 morning glories evenly spaced along the width of the box on the south side, and 8 nasturtiums evenly spaced along the north side. – user1870614 Jun 03 '16 at 13:45
  • @ kevinsky, I don't see anything weird under the leaves -- no bugs, no eggs, no color or texture abnormalities that aren't already visible from the top. – user1870614 Jun 03 '16 at 17:47
  • Did they improve? Mine looks exactly the same, and I also found a thrip, but just one. I've also seen a picture for boron deficiency on morning glories that looked the same. – Arturo Jun 28 '18 at 08:35

1 Answers1

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Had a bit of trouble working out what your container looks like, but you seem to be saying its five feet long, by 9 inches wide with a depth of 7 inches from top to bottom. Jury's still out on whether you really mean 7 inches wide and 9 inches deep from top to bottom, that's what I'm not entirely sure about.

Either way, 10 morning glories and 8 trailing nasturtiums means a lot of roots in a relatively small space, and most climbers/trailers do better with more depth of soil, rather than width, so it may be you've simply got too many plants in too shallow a container, so the reason the morning glories are stunted is because the roots are stunted.

I'd also add that nasturtiums shouldn't really be fed - they flower best in poor soil, so it's not unlikely that you'll finish up with lots of lovely leaves on the nasturtiums and very few, if any, flowers. Not good bedfellows really, plants that need feeding regularly and nasturtiums.

Bamboo
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  • You have the right idea with dimensions in the first paragraph. I tried to give the dimensions in the order you listed -- "height, width, and depth". Height is vertical, 7 inches from the soil surface to the floor of the container. Width and depth are somewhat arbitrary, but I chose the typical viewpoint of looking at the box from its broadest side, where the 5' width is the dimension perpendicular to the line of sight, and the 9" depth is (roughly) parallel to it. – user1870614 Jun 03 '16 at 17:34
  • So I interpreted it correctly then...! You might also inspect beneath the leaves, as suggested by Kevinsky, in case there's any insect invaders there... – Bamboo Jun 03 '16 at 17:35
  • I checked under the leaves and didn't find anything interesting -- I was thinking of posting a photo or two, but there's not much to see. – user1870614 Jun 03 '16 at 17:38
  • I currently have ~25 flowers on the nasturtiums, btw. – user1870614 Jun 03 '16 at 17:38
  • Ha ha, great - always got to remember that plants can't read!... So likely its the roots not having enough room then... – Bamboo Jun 03 '16 at 18:24
  • The box is actually constructed in such a way that it would be possible for me to build another box underneath it, fill that with dirt, and do a tablecloth trick with the current bottom, and if I were confident that this would help, I might do it. However, somebody grew this fine-looking morning glory vine http://www.brandylion.com/images/small-mg-full.jpg out of a "5-inch pot", which gives me pause regarding the "container to small" hypothesis. – user1870614 Jun 03 '16 at 19:18
  • hmm, if my math was better I could work out the soil volume for that pot with one plant in comparison to your container and its number of plants, but although I know its possible , its not something I know how to do, numbers not being my strong point, I get your skepticism tho, the MGs could almost have a viral infection judging by the yellow mosaicing and distortion – Bamboo Jun 03 '16 at 19:52
  • The math works out such that the plant in a hypothetical 5" pot (5" height and 5" upper diameter) gets less than 100 cubic inches of dirt, while the 18 plants in my box each have over 200 cubic inches of dirt (on average). Moreover, compared to the pot, a smaller proportion of the volume of dirt in the box will contain "edge" conditions (like a dry crust on the top surface of the soil), and the box will be less susceptible to dramatic swings in moisture and temperature. One could argue that the nasturtiums are crowding them out, but this was already a problem when all the plants were small. – user1870614 Jun 03 '16 at 20:21
  • I assume you've checked for spider mite? And there's no chance they could have been caught by herbicide spray drift? And you're certain soil ph is between 5 and 6.5? I'm out of answers now... other than the possibility of viral infection. – Bamboo Jun 03 '16 at 21:20