Cloning/Seed Starting with LEDs

Some led grow lights forum review clones and seedlings have very similar environmental needs. Growing from seed is just like it sounds —put a seed into a grow media of choice and feed/water it as necessary. Cloning is the process of taking a shoot from a donor plant and rooting it. Cloning allows for exact copies of the donor plant to be grown, so start with the strongest, healthiest donor plants for a crop of vigorous cuttings.

Also, since some plant species can produce plants that are either male or female, cloning allows the gardener to select for female-only gardens—helpful when producing flowers and fruit, without having to sort through seedlings to pick only female sprouts. Using clones is also generally faster than growing from seed.

LED grow lights are fantastic for seedlings/clones. Their compact size and ease of use can turn almost any small space into a seedling/clone garden. Even when LED grow lights were first introduced years ago, it was clear that LEDs produced strong, bushy roots on clones and strong seed starts. Early studies indicate that the higher blue-to-red ratio LED grow lights produce causes cuttings to root faster than with other lights. This is an area that needs considerably more research.

Seedlings/clones don’t need nearly as much light as plants in vegetative or flowering stages. In fact, too much light will stunt or kill them by pushing too much photosynthesis—the little seedlings/cuttings simply can’t keep up. They rely on the stored sugars in their stems and leaves, or in the seed itself, for the energy to produce roots—diverting this energy to defend against too much light will cause rooting to slow or stop, and the seedling/clone, to die.

Since clones don’t have roots at the start, their primary method to absorb water is through their leaves, which makes them fragile. Many gardeners use humidity domes over their cutting trays to keep the moisture levels up and make it easier for cuttings to absorb moisture. A humidity dome is critical for some plants but not for others. Experiment to see what works best for your environment and cuttings.

Some gardeners swear that cuttings root faster if provided with continuous light—24 hours a day. Don’t believe it—just like humans, plants need to “sleep.” This is one of those “you might get away with it” garden practices, but in the long run, cuttings rooted under continuous light won’t turn out as healthy as they would under an 18-hour photoperiod, and that can affect the performance of the plants as they mature.

Assuming you’re using a humidity dome, once your cuttings have full, bushy roots, they are almost ready to move into their next stage: vegetative growth. But first they have to be “hardened off” a process in which you slowly decrease the humidly under the dome. Clones accustomed to high humidity levels can dry out, wilt, and possibly die if the humidity is dropped to average room conditions too quickly. To harden off cuttings, lift the humidity dome and set it at an angle over the tray carefully, so you don’t crush the cuttings—for a couple of hours on the first day. This allows normal room air to penetrate the dome and reduces the humidity.

Keep a close eye on your cuttings during hardening off—many gardeners rush the process and kill many clones at this stage. Gradually increase this time for a few days adding an hour or two a day, then start leaving the humidity dome completely off for a few hours, gradually increasing this time until the cuttings are fully adjusted to normal room air conditions. At this point, the rooted cuttings are ready to move into the vegetative growth phase.

Cloning and seed-starting tips:
• Use a sharp scalpel or razor blade and make a clean cut of the shoot taken off the donor plant. If using a rooting hormone, don’t dip cuttings into original container as you could contaminate the whole bottle. Place a little bit of it in a small bowl or shot glass, then dip or roll the cutting into it, exposing for 10–30 seconds before inserting it into its rooting media.
• Feed cuttings with plain water until roots appear.
• Switch to a ¼-strength “bloom” nutrient formula after roots have started to appear. The higher phosphorus level in the bloom nutrient encourages root growth and lower level of nitrogen is perfect because too much nitrogen can actually stunt new roots.
• Don’t over-saturate the growing media. Too-wet grow media doesn’t allow air exchange in the root zone and will cause the roots to rot. Seedlings are particularly vulnerable: if they are too wet, they will rot where the stem meets the grow media and fall over—this is called “damping off.”

Author: GEHL LED
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