Question
I have actually two questions. The 1st is similar to the previous question about the Ficus Lyrata. I just purchased a fiddle leaf ficus from home depot. It had big beautiful leaves from top to bottom. I've had it for about a month and a half and the leaves at the bottom have developed brown spots and one after the other falls off.There are still very attractive leaves that look fine at the top, but when I see all the leaves at the bottom falling off, I get worried because I don't want all the leaves to fall off. I have it on the right side of a west facing window were it receives bright indirect light throughout the day and a little direct sun in the later evening. Since I've had it, I've been watering it weekly and occasionally I'll even take it and put it in the bathtub for a brief shower. I've not fed it yet because it just came from the store and I know that a lot of times the plants from a commercial grower feed the plant heavily before putting it out for sale.I'm thinking that what it's doing is normal, but it just worries me when I see so many leaves with brown spots at the bottom falling off so quickly and consecutively. My second issue is with these little gnats that look like fruit flies. They seem to be hanging around my plants quite a bit and when I shake the pots I see them around the soil when they fly out. They don't eat the leaves or suck out the sap, they just kind of burry themselves in the soil and hang around. When I did some research, I thought perhaps that they were white flies, but they don't fit the description and they're not that big nor do they hang underneath the leaves and suck the sap. I want to get rid of them because they are quite annoying, but at the same time I don't want to use pesticides unless it's absolutely necessary. What in your opinion would be the best way to get rid of them?

Answer
Hi Jamin,

Your Ficus lyrata was probably grown in brighter light than you are providing. Home Depot buys plants that have not been properly acclimated to the reduced light typically found in the home environment. A certain amount of leaf loss is inevitable, but if you are losing a lot of them, then all you can do is provide more light - move your Lyrata right in front of the west window and make sure it is uncovered throughout the day.

The shower is fine, but not necessary. Your decision not to fertilize is a good one.

One problem with Lyratas is that they rarely branch and they only grow taller and taller and eventually outgrow their space. Regular pruning of top growth is the only way to prevent that.

Those pests are fungus gnats. Adult fungus gnats fly around and are an annoyance, but they are not harmful to people. Each gnat lives for about 5 days. The trick is to get rid of the next generation - the gnat larvae that live in the top layer of the soil. The larvae feed on decaying organic matter. Decaying pine bark in potting mixes and decaying plants roots feed the larvae. Try to keep the soil as dry as possible. Remove all loose soil from the surface and put a light layer of coarse coir (coconut husk) or sand or diatomaceous earth on the soil surface. These substances have sharp edges that carve up the larvae. (Recent studies indicate that fine-textured peat moss also deters gnat larvae.)

Another safe technique is to place ?inch slices of raw potato on the surface of the soil. After a day or so, discard the slices along with the larvae inside. Repeat this until there are no more larvae in the potato.

For more serious infestations try Knock-Out Gnats to treat fungus gnats available from Gardens Alive for about $20. See http://www.gardensalive.com/item_display.asp?ProductNumber=1962

Detection trick: Add a little water to the soil and then look very closely for tiny fungus gnat larvae swimming in the water as it pools on the surface. You need good light and good eyes to see them. If you don't, then your plant is probably gnat free.

Prevention is often the best remedy. Use sterile potting mixes that are free of bark chips. The potting mix should have ample drainage material, such as perlite so that it drains well and allows the soil to dry out frequently. Fungus gnats can nearly always be traced back to overwatering and/or poor soil quality.

To attract and capture the adult flying gnats, pour a little red wine into a small glass (cooking wine will work, if you don't want to waste the good stuff!) and leave it out for the day. Repeat the treatment as necessary.

Please let me know if any of this is unclear or if you have any additional questions. If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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