Nasturtiums are usually a fairly low-maintenance plant to grow, but they are not without issues. If their leaves begin to turn yellow this can show a serious problem, but what do you do to fix it? Let’s have a look and find out.
Nasturtium Leaves Are Turning Yellow
Conversely, they can also turn yellow if they are watered too much. This is only really a problem if they are in waterlogged soil, so if this is the reason it should be fairly easy to spot.
If it is just the older leaves at the bottom of your plant turning yellow then this is normal and nothing to worry about.
This is simply the older leaves dying off, just snip them off if you find them unsightly.
What if you are sure it’s not watering-related?
Well, there can be a few other reasons why nasturtium leaves turn yellow. If you are growing in pots then it may be that the plant has become root bound.
If this is the case try potting them on into something bigger or move them into the ground.
Pest damage can also cause yellowing of leaves, look for aphids on your plant’s stems as these are a common nasturtium pest.
They suck the sap out of the plant, weakening it which can then lead to yellow leaves.
Killing Aphids On Nasturtiums
Put some gloves on, because this will get messy, and run the plant stem between your thumb and forefinger, squashing the aphids as you go.
A bucket of soapy water next to you to wash the bug juice off your gloves is a good idea as you squish. It is messy and time-consuming but you can do some serious damage to their numbers.
If, however, you don’t get them all they will soon be back so this is not a one time and done job.
One easy method of trying to keep lupin aphids off your treasured flowers is to spray them off with a high-powered hose.
This should knock the aphids off and also kill a few at the same time. This is a fairly easy method and doesn’t harm the plant at all.
Crucially though it won’t kill all of the aphids so it is more of a method to try and minimise the damage rather than get rid of the aphids altogether.
This is one of those home remedies that seem to get recommended for every problem but it can work on aphids.
The idea behind this is that you spray a diluted mix of washing-up liquid onto your aphids. The sticky spray makes it so the aphids can’t breathe and they therefore die.
It does work but it is nowhere near as effective as commercial sprays.
One issue with this method is that it can cause burn-like damage to the leaves and flowers of your plants so you do need to be careful. Just because it is not a pesticide doesn’t mean you can go spray crazy. Rinsing the plant with a follow-up water spray can really help here.
There are lots of different bug sprays that will kill aphids, some organic, some not. I always advise trying to use organic methods where possible but I can understand why you may want to try and use a proper pesticide on lupin aphids.
but I will say, just give the organic methods ago before resorting to pesticides if the other options don’t work.
- Same day, spray and eat
- Contact insecticide for ornamental plants, fruit and vegetables
- 100% natural active ingredient
- Controls greenfly, blackfly, whitefly, scale insects, mealybugs, red spider mites and other mites
- For use both indoors and outdoors all year round
While made for fruit and veg this spray can work just as well on nasturtiums.
The main active ingredient in this spray is rapeseed oil which is where the made from natural ingredients claim comes from. This spray should be a lot better for the environment and other animals than using a pesticide spray.
If you want to go the whole hog and get a heavy-duty bug spray then I recommend bug clear ultra, made by the same people as the spray above but this is the full pesticide version.
Kills all major insect pests, including whitefly, greenfly, black fly, red spider mite, caterpillars and lily beetle, scale insects and mealy bugs For use on flowers, fruit and vegetables.
Is Your Plant In The Shade?
Nasturtiums don’t like too much shade and this can be another cause of yellow leaves. If they are in pots you can move them and see if this improves things.
If they are in the ground though you are probably better off waiting until the end of the season and collecting some seeds of your plants and trying them in a different spot next year.