Strep Notes, Winter 2013-14

The last of the winter-flowering streps.

A few of our Streptocarpus bloomed over the winter, and several more grew pods of seeds. By the end of January, there were only two streps still flowering. When the last of these flowers began to droop, on another plant, the first flowers of spring were opening.

The first strep to flower this spring.

They look much alike. It seems that, in our collection at least, the light pinks are the best cool season/low light bloomers. It will be worthwhile pollinating this one (above), as it is very floriferous, in hope of richer colours in the next generation. (The pictures were taken indoors by lamp light, and expose the limitations of both my camera and my photography.)

These next few plants flowered in December. I like the dark purple (big flowers on short, very thin stems), and the clear pink with strong red lines and white face. I’ll try a few seeds from each.

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The seeds germinate quickly. 16 days is typical for us. When the leaves first appear, they are very tiny. Without a magnifying glass, you might not spot them until they are a few days old. These ones pictured are probably between a week and two weeks old. (Click pictures to enlarge.)

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We don’t give the seed trays any extra warmth. Warmth might hasten germination, but cool room temperature does the job. Once the seedlings are growing, they like cooler temperatures anyway. They also like humidity — very much. In our cold, dry part of the world, this means keeping them partly covered, at least until both of the first two leaves are growing well. A humid environment can be created inside a terrarium or converted aquarium, in a propagating chamber, a mini-greenhouse (frame and shelves with a plastic cover), inside a half-open plastic bag, etc. Along with humid air, the seedlings like a moist (not sopping wet) growing medium. Our mix is light and chunky, composed of material that is moisture-holding but also quick-drying, and broken up with bulky material such as small pebbles or grit or pieces of chopped bark.

I prick out the larger seedlings, using a toothpick, and move them into another tray where they will have more space. When the larger leaf is about 5 mm long, I place the toothpick under the leaf and my finger on top, and lift. Seedlings can be transplanted a little deeper than they were before, but the leaves should be kept completely above the growing medium.

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These hybrid streps don’t have seed leaves followed by true leaves. The seed leaves become the true leaves — or one of them does. One leaf grows faster than the other, and the other grows a little and stops. The seedlings in the next picture are about two months old. The larger leaf is now 15-20 mm long, and the second leaf is a tiny dot. These seedlings are large enough to be moved into separate small pots. Streps are shallow rooting and easily transplanted. After transplanting, if kept humid, and lightly fed with a weak fertilizer, they will grow quickly.

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This next seedling’s first-grown leaf is 4.5 cm long. The second leaf is still here but not growing. Above the second leaf, a third leaf has sprung from the base of the first. Roots can also be seen just above the soil. Kept humid (under a baggie tent, in this case), the seedlings will develop adventitious roots that draw moisture from the air while they reach for the soil. This seedling has been transplanted three times. In its own 8 cm pot now, it has plenty of room to grow for at least a year.

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These lengthening days, the mature plants are forming new flowering buds.

Older leaves that are not producing buds will be removed. An old leaf that is producing new leaves at its base will be sliced off above the new leaves. (These new leaves, cut away from the main plant along with a few roots, can be raised into a new plant.) We like to keep the plants small because we have many of them and many more on the way. A seedling can be grown to flowering size in a container as small as a shot glass, and then the decision made to move it into a larger pot or discard it.

I haven’t had much success yet in propagating new plants from leaf cuttings but have learned a few things. Old leaves that have produced a few flower stems are not the best candidates. Younger leaves (around 15-20 cm long) have more grow-juice in them. (Apologies for the scientific jargon.) The air around the leaf cutting should be humid and the rooting medium just damp. Not wet — not even moist. Anything more than damp, and the leaf will rot. (Almost all of the leaves I’ve tried so far have rotted.) Neglect, rather than close monitoring and fussy attention, is more likely to bring success.

Leaves or leaf cuttings will produce adventitious roots if the humidity is fairly high. A small number of new plants can be produced by wrapping a leaf in damp (not wet!) paper (e.g. a clean coffee filtre) and keeping this in a plastic bag. If no new roots or leaves appear after six weeks, or if the leaf turns grey-brown, throw it out and start again.

The next photos show new plants grown from leaves or cuttings wrapped in damp paper.

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Another method to try is to lay cuttings, face up, on damp (!) growing medium, weight them down with bits of bark or pebbles, and keep them humid. In this picture (click to enlarge), there is a new plant at the far right and one at the far left (lighter green). Eventually, before it decomposed, this chopped up leaf produced four new plants.

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So far, for me, seeds are the more reliable source of new plants. Seeds are easy and will produce flowering-size plants just as soon as leaf cuttings will, maybe sooner. Of course, if you have some very special plants and really want to produce numerous clones, you will find a method that works (as I intend to do), though you might lose a few leaves along the way.

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This entry was posted in houseplants, how-to, indoor gardening, Seeds for Sale, streptocarpus, winter and tagged , , . Bookmark the permalink.

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