Dark Heart Nursery’s premium clones are grown in 2 inch rockwool cubes, and our Heartlet clones are grown in 1 1/2 inch rockwool cubes. Rockwool is an ideal media for because it has an excellent water-to-air content ratio that promotes strong root growth. It is also an easy media to transplant into any other media (soil, coco, rockwool slab, clay pellets, etc). Our premium clones’ two inch cubes provide them ample room for strong root development, the smaller cubes of our Heartlet clones allows for easier storage and transportation.

Storing Cubes Temporarily

Ideally, Dark Heart clones should be planted as soon as you bring them home. However, in some cases this is not practical. If you do need to store them temporarily before transplanting we suggest the following.

Water your clones with a dilute nutrient solution (400 to 600 ppm) and place them under a low intensity  fluorescent fixture; T8 or T12 bulbs are idea for this purpose, T5 bulbs are more intense and can cause plants to begin “stretching” before you are ready. Be sure to keep the cubes moist, but don’t allow standing water to accumulate in the tray. This step will cause the rate of growth to slow, keeping them a manageable size, and ensuring that some clones aren’t dwarfed because they are shaded out by larger ones.

As your clones do begin to stretch be sure to rearrange them to prevent some clones from being “shaded out” and transplant them as soon as possible.

Preparing for Transplanting

First Prepare your media. Some types of media require soaking, conditioning, or some other form of preparation. Coco coir blocks, for example, need to be soaked and then broken up. Pre-mixed coco coir substrates are easy to work with and can be forgiving. Popular amendments include organic or synthetic fertilizer, oyster shell meal (for pH buffering), and various substances to improve soil structure.

Next, Fill your pots with your chosen media. Fill to 1 inch from lip of pot and gently tamp soil by pressing it down with your hand. By gently tamping you help ensure that air pockets have not developed in the pot; air pockets can dry out your roots and will negatively affect plant health. After tamping you should have 1 1/2 to 2 inches of space between the lip of the pot and the media. This space is important so that you do not overflow the pot while watering.

Pro Tip:

Some growers reduce “transplant shock” to their clones by soaking them in a vitamin and hormone solution such as Super Thrive. Super Thrive and similar products contain vitamins and hormones that are reported to minimize stress on growing plants. Prepare a batch by mixing
one gallon of water with ¼ teaspoon of concentrate. Soak clones for 15 minutes before

Dark Heart Clones Are Easy to Transplant:

First, Dig a small well in the media about twice the size of the cube (3 to 4 inches square). Place the clone  in well. The top of the cube should be level with the media. If the rockwool cube is exposed to too much air it will dry out easily. If the media level is above the cube it may come into contact with the stem. This can cause fungal disease.

The stem of the clone should be as vertical as possible. Sometimes this means that the rockwool cube will need to be planted crooked. We find that having a vertical stem leads to superior growing results.

Next, fill in media around the clone’s cube. Be sure that the bottom and sides of the cube are in good contact with the media. The rockwool cube should be planted so that just the very top of the cube is exposed. If the cube becomes exposed through watering, gently pack some soil back around it. After several weeks the clone will be well enough rooted that this will not be an issue.

Finally, thoroughly water in in your newly transplanted clone. Thorough initial watering helps ensure there are no air pockets or try spots in your media, and that the cube comes into good contact with it.

For the first week or two be sure to check the moisture of the actual rockwool cube. In some cases it is possible for the potting media to wick moisture away from the cube. In these cases the potting media would be moist, but the cube may be too dry to support the plant. If this happens pour about 1 cup of irrigation water onto the cube itself. Within two weeks the plant will develop a stronger root system, and this will not be an issue.

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