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Marijuana Botany by Robert Connel Clark
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<blockquote data-quote="cannebosanac" data-source="post: 20018" data-attributes="member: 1357"><p>poglavlje 2 nastavak</p><p></p><p>The cuttings usually develop a good root system and </p><p>will be ready to transplant in three to six weeks. At this </p><p>time the hardening-off process begins, preparing the deli- </p><p>cate cuttings for a life in bright sunshine. The cuttings are </p><p>removed and transplanted to a sheltered spot such as a </p><p>greenhouse until they begin to grow on their own. It is </p><p>necessary to water them with a dilute nutrient solution or </p><p>feed with finished compost as soon as the hardening-off </p><p>process begins. Young roots are very tender and great care </p><p>is necessary to avoid damage. When vegetative cuttings are </p><p>placed outside under the prevailing photoperiod they will </p><p>react accordingly. If it is not the proper time of the year </p><p>for the cuttings to grow and mature properly (near harvest </p><p>time, for example) or if it is too cold for them to be put </p><p>out, then they may be kept in a vegetative condition by </p><p>supplementing their light to increase daylength. Alterna- </p><p>tively they may be induced to flower indoors under arti- </p><p>ficial conditions. After shoots are selected and prepared for cloning, </p><p>they are treated and placed in the rooting medium. Since </p><p>the discovery in 1984 that auxins such as IAA stimulate </p><p>the production of adventitious roots, and the subsequent </p><p>discovery that the application of synthetic auxins such as </p><p>NAA increase the rate of root production, many new tech- </p><p>niques of treatment have appeared. It has been found that </p><p>mixtures of growth regulators are often more effective </p><p>than one alone. IAA and NAA a--e often combined with a </p><p>small percentage of certain phenoxy compounds and fungi- </p><p>cides in commercial preparations. Many growth regulators </p><p>deteriorate rapidly, and fresh solutions are made up as </p><p>needed. Treatments with vitamin B1 (thiamine) seem to </p><p>help roots grow, but no inductive effect has been noticed. </p><p>As soon as roots emerge, nutrients are necessary; the shoot </p><p>cannot maintain growth for long on its own reserves. A </p><p>complete complement of nutrients in the rooting medium </p><p>certainly helps root growth; nitrogen is especially bene- </p><p>ficial. Cuttings are extremely susceptible to fungus attack, </p><p>and conditions conducive to rooting are also favorable to </p><p>the growth of fungus. "Cap tan " is a long-lasting fungicide </p><p>that is sometimes applied in powdered form along with </p><p>growth regulators. This is done by rolling the basal end of </p><p>the cutting in the powder before placing it in the rooting </p><p>medium. </p><p>Oxygen and Rooting </p><p>The initiation and growth of roots depends upon </p><p>atmospheric oxygen. If oxygen levels are low, shoots may </p><p>fail to produce roots and rooting will certainly be inhibited. </p><p>It is very important to select a light, well-aerated rooting </p><p>medium. In addition to natural aeration from the atmos- </p><p>phere, rooting media may be enriched with oxygen (02) </p><p>gas; enriched rooting solutions have been shown to increase </p><p>rooting in many plant species. No threshold for damage by </p><p>excess oxygenation has been determined, although exces- </p><p>sive oxygenation could displace carbon dioxide which is </p><p>also vital for proper root initiation and growth. If oxygen </p><p>levels are low, roots will form only near the surface of the </p><p>medium, whereas with adequate oxygen levels, roots will </p><p>tend to form along the entire length of the implanted </p><p>shoot, especially at the cut end. </p><p>Oxygen enrichment of rooting media is fairly simple. </p><p>Since shoot cuttings must be constantly wetted to ensure </p><p>proper rooting, aeration of the rooting media may be facili- </p><p>tated by aerating the water used in irrigation. Mist systems </p><p>achieve this automatically because they deliver a fine mist </p><p>(high in dissolved oxygen) to the leaves, from where much </p><p>of it runs off into the soil, aiding rooting. Oxygen enrich- </p><p>ment of irrigation water is accomplished by installing an </p><p>aerator in the main water line so that atmospheric oxygen </p><p>can be absorbed by the water. An increase in dissolved </p><p>oxygen of only 20 parts per million may have a great in- </p><p>fluence on rooting. Aeration is a convenient way to add </p><p>oxygen to water as it also adds carbon dioxide from the </p><p>atmosphere. Air from a small pump or bottled oxygen may </p><p>also be supplied directly to the rooting media through tiny </p><p>tubes with pin holes, or through a porous stone such as </p><p>those used to aerate aquariums. </p><p>Rooting Media </p><p>Water is a common medium for rooting. It is inexpen- </p><p>sive, disperses nutrients evenly, and allows direct observa- </p><p>tion of root development. However, several problems arise. </p><p>A water medium allows light to reach the submerged stem, </p><p>delaying etiolation and slowing root growth. Water also </p><p>promotes the growth of water molds and other fungi, sup- </p><p>ports the cutting poorly, and restricts air circulation to the </p><p>young roots. In a well aerated solution, roots will appear in </p><p>great profusion at the base of the stem, while in a poorly </p><p>aerated or stagnant solution only a few roots will form at </p><p>the surface, where direct oxygen exchange occurs. If root- </p><p>ings are made in pure water, the solution might be replaced </p><p>regularly with tap water, which should contain sufficient </p><p>oxygen for a short period. If nutrient solutions are used, a </p><p>system is needed to oxygenate the solution. The nutrient </p><p>solution does become concentrated by evaporation, and </p><p>this is watched. Pure water is used to dilute rooting solu- </p><p>tions and refill rooting containers. </p><p>Soil Treatment </p><p>Solid media provide anchors for cuttings, plenty of </p><p>darkness to promote etiolation and root growth, and suffi- </p><p>cient air circulation to the young roots. A high-quality soil </p><p>with good drainage such as that used for seed germination </p><p>is often used but the soil must be carefully sterilized to </p><p>prevent the growth of harmful bacteria and fungus. A small </p><p>amount of soil can easily be sterilized by spreading it out </p><p>on a cookie sheet and heating it in an oven set at "low," </p><p>approximately 820 C (180~ F), for thirty minutes. This kills </p><p>most harmful bacteria and fungus as well as nematodes, in- </p><p>sects and most weed seeds. Overheating the soil will cause </p><p>the breakdown of nutrients and organic complexes and the </p><p>formation of toxic compounds. Large amounts of soil may </p><p>be treated by chemical fumigants. Chemical fumigation </p><p>avoids the breakdown of organic material by heat and may </p><p>result in a better rooting mix. Formaldehyde is an excellent </p><p>fungicide and kills some weed seeds, nematodes, and in- </p><p>sects. One gallon of commercial formalin (40% strength) is </p><p>mixed with 50 gallons of water and slowly applied until </p><p>each cubic foot of soil absorbs 2-4 quarts of solution. </p><p>Small containers are sealed with plastic bags; large flats and </p><p>plots are covered with polyethylene sheets. After 24 hours </p><p>the seal is removed and the soil is allowed to dry for two </p><p>weeks or until the odor of formaldehyde is no longer </p><p>present. The treated soil is drenched with water prior to </p><p>use. Fumigants such as formaldehyde, methyl bromide </p><p>or other lethal gases are very dangerous and cultivators </p><p>use them only outside with appropriate protection for </p><p>themselves.</p></blockquote><p></p>
[QUOTE="cannebosanac, post: 20018, member: 1357"] poglavlje 2 nastavak The cuttings usually develop a good root system and will be ready to transplant in three to six weeks. At this time the hardening-off process begins, preparing the deli- cate cuttings for a life in bright sunshine. The cuttings are removed and transplanted to a sheltered spot such as a greenhouse until they begin to grow on their own. It is necessary to water them with a dilute nutrient solution or feed with finished compost as soon as the hardening-off process begins. Young roots are very tender and great care is necessary to avoid damage. When vegetative cuttings are placed outside under the prevailing photoperiod they will react accordingly. If it is not the proper time of the year for the cuttings to grow and mature properly (near harvest time, for example) or if it is too cold for them to be put out, then they may be kept in a vegetative condition by supplementing their light to increase daylength. Alterna- tively they may be induced to flower indoors under arti- ficial conditions. After shoots are selected and prepared for cloning, they are treated and placed in the rooting medium. Since the discovery in 1984 that auxins such as IAA stimulate the production of adventitious roots, and the subsequent discovery that the application of synthetic auxins such as NAA increase the rate of root production, many new tech- niques of treatment have appeared. It has been found that mixtures of growth regulators are often more effective than one alone. IAA and NAA a--e often combined with a small percentage of certain phenoxy compounds and fungi- cides in commercial preparations. Many growth regulators deteriorate rapidly, and fresh solutions are made up as needed. Treatments with vitamin B1 (thiamine) seem to help roots grow, but no inductive effect has been noticed. As soon as roots emerge, nutrients are necessary; the shoot cannot maintain growth for long on its own reserves. A complete complement of nutrients in the rooting medium certainly helps root growth; nitrogen is especially bene- ficial. Cuttings are extremely susceptible to fungus attack, and conditions conducive to rooting are also favorable to the growth of fungus. "Cap tan " is a long-lasting fungicide that is sometimes applied in powdered form along with growth regulators. This is done by rolling the basal end of the cutting in the powder before placing it in the rooting medium. Oxygen and Rooting The initiation and growth of roots depends upon atmospheric oxygen. If oxygen levels are low, shoots may fail to produce roots and rooting will certainly be inhibited. It is very important to select a light, well-aerated rooting medium. In addition to natural aeration from the atmos- phere, rooting media may be enriched with oxygen (02) gas; enriched rooting solutions have been shown to increase rooting in many plant species. No threshold for damage by excess oxygenation has been determined, although exces- sive oxygenation could displace carbon dioxide which is also vital for proper root initiation and growth. If oxygen levels are low, roots will form only near the surface of the medium, whereas with adequate oxygen levels, roots will tend to form along the entire length of the implanted shoot, especially at the cut end. Oxygen enrichment of rooting media is fairly simple. Since shoot cuttings must be constantly wetted to ensure proper rooting, aeration of the rooting media may be facili- tated by aerating the water used in irrigation. Mist systems achieve this automatically because they deliver a fine mist (high in dissolved oxygen) to the leaves, from where much of it runs off into the soil, aiding rooting. Oxygen enrich- ment of irrigation water is accomplished by installing an aerator in the main water line so that atmospheric oxygen can be absorbed by the water. An increase in dissolved oxygen of only 20 parts per million may have a great in- fluence on rooting. Aeration is a convenient way to add oxygen to water as it also adds carbon dioxide from the atmosphere. Air from a small pump or bottled oxygen may also be supplied directly to the rooting media through tiny tubes with pin holes, or through a porous stone such as those used to aerate aquariums. Rooting Media Water is a common medium for rooting. It is inexpen- sive, disperses nutrients evenly, and allows direct observa- tion of root development. However, several problems arise. A water medium allows light to reach the submerged stem, delaying etiolation and slowing root growth. Water also promotes the growth of water molds and other fungi, sup- ports the cutting poorly, and restricts air circulation to the young roots. In a well aerated solution, roots will appear in great profusion at the base of the stem, while in a poorly aerated or stagnant solution only a few roots will form at the surface, where direct oxygen exchange occurs. If root- ings are made in pure water, the solution might be replaced regularly with tap water, which should contain sufficient oxygen for a short period. If nutrient solutions are used, a system is needed to oxygenate the solution. The nutrient solution does become concentrated by evaporation, and this is watched. Pure water is used to dilute rooting solu- tions and refill rooting containers. Soil Treatment Solid media provide anchors for cuttings, plenty of darkness to promote etiolation and root growth, and suffi- cient air circulation to the young roots. A high-quality soil with good drainage such as that used for seed germination is often used but the soil must be carefully sterilized to prevent the growth of harmful bacteria and fungus. A small amount of soil can easily be sterilized by spreading it out on a cookie sheet and heating it in an oven set at "low," approximately 820 C (180~ F), for thirty minutes. This kills most harmful bacteria and fungus as well as nematodes, in- sects and most weed seeds. Overheating the soil will cause the breakdown of nutrients and organic complexes and the formation of toxic compounds. Large amounts of soil may be treated by chemical fumigants. Chemical fumigation avoids the breakdown of organic material by heat and may result in a better rooting mix. Formaldehyde is an excellent fungicide and kills some weed seeds, nematodes, and in- sects. One gallon of commercial formalin (40% strength) is mixed with 50 gallons of water and slowly applied until each cubic foot of soil absorbs 2-4 quarts of solution. Small containers are sealed with plastic bags; large flats and plots are covered with polyethylene sheets. After 24 hours the seal is removed and the soil is allowed to dry for two weeks or until the odor of formaldehyde is no longer present. The treated soil is drenched with water prior to use. Fumigants such as formaldehyde, methyl bromide or other lethal gases are very dangerous and cultivators use them only outside with appropriate protection for themselves. [/QUOTE]
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