The Weird Horticultural World of Rapitest



I was persuaded to buy a moisture meter when I bought some potted citrus trees recently.  Citrus trees are very finicky about moisture when they are grown in a pot, and the proper way to judge their water needs is to check the moisture about 4 inches below the soil line. A moisture meter only costs 10 or 15 bucks, so it seemed like a reasonable investment considering that I would be repaid in Meyer lemons.

So far, so good. The citrus growers told me how to take the reading and when to water, so I didn’t really need the instructions that came with the meter.

But of course I read the instructions anyway, the way one compulsively reads a box of cereal at the kitchen table, and it was there that I was introduced to Luster Leaf company’s very strange ideas about the sorts of plants that its customers grow. I refer to this list, which tells you what the meter should read before you water that particular plant, along with instructions about frequency of watering and other special needs.


Tomatoes are not on the list. Nor is basil. Ficus tree, an ordinary sort of houseplant, cannot be found, nor can such average garden plants as hosta, hydrangea, rose, or rhododendron.  Japanese maples are nowhere on the list, in spite of the fact that this is exactly the sort of fancy plant a fussy gardener might monitor with a moisture meter. Dahlias are likewise not on the list.

What can you find?  Here’s a selection of actual plant names for which Luster Leaf feels you might require additional watering information.

Burro’s Tail

Cupid’s Bower

Fat-Headed Lizzie

Flame of the Woods

Friendship Plant

Gold-Dust Plant

Jelly Bean Plant

Lipstick Vine

Mosses (sic)-in-the-Cradle

Painters Palette

Parlour Plant

Piggyback Plant

Shrimp Plant

Snakeskin Plant

Vase Plant

Yesterday, Today, Tomorrow

Zebra Plant

Quick:  Without Googling them, how many of these plants have you EVER heard of?  I made a point of not looking any of these up just to make the point that a gardener with slightly above-average plant knowledge cannot make heads or tails of this list.  Forget the fact that there are no Latin names on the list, forget the fact that whoever compiled the list chose the silliest possible common name out there.

My question is–Doesn’t anyone involved with this moisture meter actually garden?  Do they honestly think we need more information on how to water our Fat-Headed Lizzie than our cherry tomatoes?

In their defense, there is an outdoor watering guide on their website that gives some suggestions for watering more common garden plants, but you wouldn’t find that out by reading their packaging, which contains only the strange and confusing list of nonsensical plant names I mentioned above.


  1. How about this instruction from their insert?
    “Cacti and Succulents:These plants store water and require less attention than other plants. From March to September, do not allow the soil to dry out.”

    I’m no cactus expert, but not letting them dry out – really?

  2. Without googling, I could put a real plant to five of those common names. Since most house plants are tropicals you would think I would know more. Is this a China based company with different names for common tropical house plants that get an additional twist in translation?

  3. “My question is–Doesn’t anyone involved with this moisture meter actually garden? ”


    As with some of the compost bins out there, some of the people generating these products seem to be tinkerers looking for a market. And guilt-and-worry ridden gardeners seem to be a good market. I’m fond of describing products like this and “weedblock” fabric as “the victory of marketing over utility.”

    And I grow Meyer lemon, Clementine tangerine, Calamondin orange and Meiwa kumquats in pots very successfully without resorting to a water meter. How? All the pots have a mulch of either river pebbles or wine corks (standing on end, they’re very attractive) so the pots hold water longer and I water them when one of them shows a bit of leaf curl. (duh–who knew plants came with their own “moisture meters” ?)

    Good luck with your Meyer–you might enjoy my post on applying organic fertilizer to my mobile citrus grove–

    Also a recipe: every January when the Meyer lemons are ripe, my wife and I enjoy a little ritual. While she is whipping up some crepes, I’m dicing the lemons, edible skin and all, into little half inch cubes. We sprinkle the lemon in a line down a crepe and then sprinkle some brown sugar on the lemon. Roll ’em up and eat ’em with the juices running down your chin. OMG. The flavor is incredible, but I really savor the contrast of textures–succulent lemon skins, creamy crepe and crunchy brown sugar.

    Bon apetite.

  4. Sadly, I know them all. I did a seven-month sentence as Live Nursery Specialist for a big-box garden center, and as a result I have heard every common house/garden plant name in existence I’m sure. Botanical Latin, anyone? Not there!
    My favorite of all time – customer asking about her “hygeraniums”. They were blue and she wanted them pink. What should she put on them to change their color?

  5. “But of course I read the instructions anyway, the way one compulsively reads a box of cereal at the kitchen table” I love that line.

    Living in Florida, I recognize most of those plant’s names but they are a bit off from the usual common names…

    First of all, friendship plant can be used to describe all sorts of plants that are propagated and shared. Billbergia nutans is only one of them, and they get watered in the vase, not the soil. “Vase plant” can describe any bromeliad, and they don’t need water in the soil either, and will often rot if the soil’s wet! You’re right, they probably have no experience gardening whatsoever.

  6. There are at least two plants on that list that I recognize as each belonging to two very different species (tropical vs succulent). I recognize a few more, but the fact that I see two which could be mistaken makes me doubt that the plant in my care is the same one they list.

    When it comes to moisture meters – well the RapiTest is more sophisticated, but my son (eight at the time) made me a meter from his Electro-Mag kit. Two long screws, two wires, a battery pack, small light bulb & a few connecting magnetic thingies & I can test my plant soil for moisture content (brighter light = higher moisture). This is packaged more prettily, but I wonder if the science behind it is really any different ?

  7. I am glad that you did all the dirty work for us. I do not have extra money to try new things. I will tell all of my friends about your report. They will appreciate it, too.

  8. Well, the moisture meter you are using probably is most often utilized by those who grow indoor plants. I agree that it is perhaps inconsiderate of the company not to list the proper names of the plants. But I can assure you that the students in my interiorscape class would be able to name many, if not most of the plants listed.

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