Jade summered out well, slumped after coming back in


I discovered mold on many of my jade plant's

lower leaves about two weeks ago. I have been picking off several new moldy leaves each day. I haven't watered it since it came in the house in early October and the soil is very dry. Because of all the rain we had in the fall I was covering it with a thin plastic table cloth when it rained, but the soil was pretty wet when I brought it in. It is on a stand in front of a sliding door which is on the east side of the house. Would some artificial light help? If so could I use a light bulb on an unshaded floor lamp? How about a fungicide? - D -


Light will always help a jade (Crassula species). Use a fluorescent fixture or bulb. If an incandescent bulb is all you have, use it, but it won't be so much help as a fluorescent bulb since it has to be further away (see Plants and Artificial Light, below) to avoid cooking the plant.


White's all right if the leaf's firm

About the moldy leaves: It's a great that you noticed them right away, and are picking them off as you see them. If they're still pretty firm in feel and the white coating is one you can rub off (photo above), that's probably powdery mildew. It should be enough to remove infected leaves and give the plant better light and air on its remaining leaves -- thinning its foliage is one way to do that.

If the moldy leaves are more gray than white, and soft to mushy, the plant may have a Botrytis infection. Gray mold/Botrytis is more serious than mildew so you may lose more of the plant before it's beaten. However, it's an ailment that responds to the same controls -- cleanliness and giving the plant the light energy it needs to regroup.


Fungicide: Doesn't release you from other control measures

About fungicide: We wouldn't. It might help against mildew or Botrytis but using it will not excuse you from doing all the rest, because all it can do is prevent new infection. It won't cure what's already within the plant's stems and leaves. The "mold" we see is the mature, reproductive face of the fungus. The fungus has been in residence for some time when we see that.

You can learn about watering succulents from some of the photos included here, and also something about the value of saying, "Let's go see": We dropped in on friends with jades, looking for mildew. We found it on a few leaves of a densely-leafed jade sitting on a shelf in a conservatory against the solid back wall. "Oh, look at you!" Its gardener said, "You were fine while it was summer but now that it's winter you can't handle that stuffy shelf, can you?" Then she moved the plant from its place against the wall, out to a place where light and air will flow all around it.


Looking at the jade on the shelf from straight on (blue arrow), we bet you can't tell the air flow there is compromised. But look again from the side (shown below) and see the giant monkey paw plants blocking air and light from the side.


Jades under cover of plastic: Not happy campers!

We understand your concern about a jade being too wet outdoors, but next year don't cover it in plastic. As water moves into the root zone from adjacent soil -- something you can't stop -- the earth begins to exhale humid air. Then, plastic can trap lots of moisture around the foliage. Unless you're there to remove the sheet the minute the rain stops, fungus will have more hours of dampness and thus more chance to take hold than it would have otherwise.

It's enough to make sure the ground or potting mix around the roots drains perfectly. Even though the plants can survive long dry spells, they do handle rain in the wild. Our jades -- our own and those of clients -- are out in the weather all summer, planted in coarse builder's sand in pots with clear drain holes, or in that same sand in-ground in spots where excess water can fall quickly through and below the garden soil.


Plants and artificial light: Make it cozy!

Light's energy level drops drastically with distance -- move a plant two feet from a light source and it loses 75% of the energy.

It may also lose its friends -- Olive, here in our jade, was not only enjoying sitting in an elevated perch, but basking in the light we keep shining on the tree!



Fat leaves tell tales!

When you see that a plant's leaves can swell and hold water, as many succulents do, you might think "Keep this plant dry. You're right -- part of the time! Leaves that hold water are an indication that at least some time during the year in its native clime, that plant has plenty of water available, can handle that and store it as a hedge against drier times.

It's simple to judge a leaf's turgidity by feel. A little tougher to learn here, by eye. Yet you should be able to tell that the leaf on the left is more plump, the one on the right thinner -- not thin enough to need water, however. That's where touch comes into play, when the leaf is thin and has also lost its firm feel.

ThickestJade2128.jpg ThinJade2118.jpg

Plants staying healthy: Thinner during winter

Don't worry too much over leaf loss when you bring plants indoors for winter. Many plants thin themselves by half, or more, as an adjustment to lower light inside. Some do this drastically, some more gradually.


Watering a succulent plant during dormancy

In winter, when days are short so jades are resting, don't water until the individual leaves begin to get thin. If the leaves look plump and feel firm, hold off watering even if the soil is really dry. None of the leaves shown here are thin enough to be  thirsty -- when their time comes they may even show wrinkles at their thinnest. The gardener must develop a feel for that condition, in order to give the roots the dry, airy rest that keeps them healthy.

Our jades' root balls are bone dry in winter more often than they're moist. Yet the leaves remain turgid -- plump -- so we leave them alone. Those inside our house may need water only twice in all of winter, before they resume growth in March's growing light. Those wintering in a friend's dark, cool root cellar will probably go the whole winter without water.


Hope we helped save your jade, too!

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