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Growing Things: Prune annuals and water well to prevent indoor yellowing

When overwintering annuals such as geraniums indoors, Gerald Filipski recommends pruning them back and providing plenty of water to prevent yellowing.
When overwintering annuals such as geraniums indoors, Gerald Filipski recommends pruning them back and providing plenty of water to prevent yellowing.

Q: I hope you can help me with a problem. This year I decided to save two favourite annuals by overwintering them. One is a scented geranium and the other a beautiful pansy whose name escapes me. When I brought them in, I repotted them both, added some slow-release fertilizer and watered them well. Then I placed them in a sunny window. Within three days the geranium leaves started to look yellow, and that continued until all the bottom leaves were yellow and starting to drop off. Can you tell me if it is something I did or didn’t do?

A: The older leaves of most annuals will begin to turn yellow as they are moved indoors. Pruning back the plants will help to encourage new growth that will take the place of the leaves that have yellowed and fallen off. I suggest cutting back the plants by a quarter before bringing them indoors.

Another possible cause of the yellowing may be due to the fact that geraniums are not big fans of having their roots disturbed. Finally, most plants will go into a bit of shock just by being moved into the indoor environment. Prune the plants back, keep them well watered and in a sunny location and they may come back for you.

Q: I have been growing glads for years and sometime they come out of the soil larger than they went in, but most of the time they seem to shrink. How do I get them to grow larger all the time? I am assuming that the larger bulbs will produce a larger flower.

A: It is true that the larger the corm the larger the bloom. The reason that the corms shrink is that the nutrients that are stored in the corm are used to produce the bloom and leaves. Because of a lack of nutrients available for uptake the plant is unable to store more nutrients in the corm in the fall. To prevent this from happening you need to fertilize glads twice a year. Use 10-10-10 and apply when preparing the bed for planting and again after the first spikes emerge. Follow the manufacturer’s directions for the amount to apply.

Another key is to allow the plant to dieback naturally in the fall. This means letting it get killed by the frost and then waiting until the leaves yellow. If you cut off the leaves before the plant has been touched by frost and been allowed to dieback you will lose the nutrients that are in the leaves that would have been stored back in the corm.

Q: I have an indoor banana plant. I have been growing it for several years but this year the leaves are turning brown. How can I remedy this?

A: First, let me congratulate you on growing the banana, which can be a very finicky plant. Without seeing the plant my best guess would be a humidity issue. Lack of humidity can cause the problem you described. Bananas need all the humidity you can offer, especially in our dry indoor winter conditions. Also, a lack of water could be the problem. Bananas love to have moist soil. Don’t allow the soil to dry out completely between waterings.

Another possibility, if the lower leaves are browning then it might be part of the natural process that bananas go through where they lose their lower leaves as they grow newer top ones.

Q: I have some leftover seeds from last year. I have them in an airtight container in the fridge. Do you think they will be good to use this year?

A: It sounds like you have done everything right when it comes to storing the seeds. The seeds should still be viable this year. You may get a bit of a lower percentage of germination than last year but they should still give good performance.

Gerald Filipski is the author of Just Ask Jerry. E-mail your questions to filipskigerald@gmail.com . To read previous columns, go to edmontonjournal.com/filipski

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