1. Life & Culture

Diggin' Florida Dirt: Houseplant tips from a pro

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Published Oct. 4, 2012

If there's a database of habitual houseplant abusers, I'm surely in it now. Darn it. • I have just five houseplants because, frankly, most die under my watch. However, my areca palms — ironically, from funeral dish gardens — angelwing and Rex begonias, arrowhead plants and watermelon peperomia are thriving (more or less) near their respective windows. • I've had such luck with them, I thought I had turned a corner. Wrong! Some misadventures in office plant gardening (a plague of fungal gnats prompted complaints to human resources and a general chill when I joined water-cooler chats) prompted a call to an expert who came highly recommended by a reader.

Steve Stanford is president of Plantz.US, a Tampa company that dates back to the 1970s. Steve has been running it for eight years. The company rents plants to businesses from Brooksville to Sarasota, Clearwater to Winter Haven. It also designs and maintains indoor landscaping. (And does the same for homeowners, but those customers buy the plants instead of renting them.)

Steve shattered every illusion I had about caring for houseplants. Which explains my poor track record. His most frequent answer to my questions? NO!

So, Steve, I understand it's good to set your houseplants out under the trees in the summertime, when the humidity cranks up, so they get a little vacation from the stuffy indoors, right?

NO! (Gasp.) We never put an interior plant outside! There are too many critters outside. If a plant is doing well inside, there's no reason to move it. Plants get accustomed to their conditions — the light levels, the temperature. If it's doing good inside, don't move it.

Okay, how about repotting new plants? You should definitely get that done pretty soon after you buy them, shouldn't you?

NO! (Choking noises.) In most cases, indoor plants should not be repotted. If the plant was grown in an interior environment and it was healthy there, then it has the root system necessary to sustain itself.

For most indoor applications, plants are purchased and installed at about the desired size. If you put it in a bigger pot and allow it to grow much bigger than it was intended, it will develop a bigger root system to support the new top growth. Then it becomes root-bound.

Just put the grow pot in a decorative container and cover the top with sheet moss to hide the grow pot.

Disturbing a new indoor plant by repotting it is the second best way to kill it.

Second best? What's the first best?

Overwatering. That kills them quicker than not watering enough.

What do you recommend for fertilizing? Monthly? A slow-release variety?

No and no. When plants are indoors, their metabolism slows down. The plant doesn't need much nutrition. New plants have enough fertilizer in the soil to be fine for a year. After that, lightly fertilize once every three months or so with a complete fertilizer — one with minor elements (such as copper, zinc and magnesium).

Don't use the slow-release varieties. They're for the outdoors.

Ever hear of fungal gnats?

Yes! (Ah!) Fungal gnats are probably the biggest pain in the rear in my industry. They disappear for a couple of days, go down in the soil and do their thing, and then they reappear. You can't have them in a business environment.

(You're tellin' me! If you haven't experienced fungal gnats, they're smaller than fruit flies and breed in damp soil. Then they take wing, flying into your co-workers' mouths while they're eating or having really important conversations. They don't hurt the plants, Steve says, but they sure do annoy the people.)

Put up one of those yellow sticky fly traps to get rid of the grownups and let the soil dry out so they won't breed. (If that doesn't work, Steve likes Gnatrol, an organic, biological pesticide available on Amazon.)

Any other pests we should look out for indoors?

Mealybugs, mites and scale. I'll get calls for cockroaches and other things, but they're just hanging out in the planters — they're not bugging the plants.

For plant pests, the first best thing to do is remove as many as you can mechanically. (Pick them off and kill them.) The best pesticide is light dish soap and water and a sponge. Wash the leaves. Don't use an abrasive soap, and you don't need to rinse.

I guess I'm guilty of some pretty serious houseplant abuses. What sorts of horrendous things do you see in offices?

Plants get used as coat hangers and Christmas trees when it's not Christmas. We work in medical environments and I've seen despicable things there.

So, I certainly feel vindicated. I may move, repot and overfertilize, but I do not throw up in my plants!

Steve gave me lots more information, including good plants for indoors, tips on lighting, and a cool little watering system he recommends called PlantAssure. So stay tuned — I'll offer another session of houseplant offender rehab in the weeks ahead.

Reach Penny Carnathan at Read more local gardening tales on her blog,, or join in the chat on Facebook, Diggin Florida Dirt.