Strong Stems

STRONG STEMS,HEALTHY PLANTS

bY MATT LEbANNiSTEr

The three main culprits of weak or stretched stems and ways to toughen them up.

There are many variables that must be considered when setting out to grow consistently healthy plants. When growing indoors, gardeners must take responsibility for meeting all of their plants’ needs. However, having the right knowledge can give indoor gardeners a big advantage over outdoor growers, because while traditional outdoor gardeners are more or less at the mercy of their local soil and weather conditions, indoor growers have the ability to maximize crop potential by customizing the growing environment to meet their plants’ specific requirements.

68 Maximum Yield USA | April 2011


Controlling temperature indoors means there are no unexpected spring frosts or protracted heat waves, while having the abil-ity to feed plants frequently with a nutrient solution specifically designed for each stage of growth allows the indoor gardener to fully meet the plants’ nutritional needs. Natural sunlight is replaced by light bulbs de-signed to mimic the sun, but also to give plants the perfect intensity and spectrum for their particular stage of growth. Plants can be watered fre-quently and allowed to drain, keeping them from drying out or drowning. The only real disadvantage facing indoor gardeners, in fact, is that they are in complete charge of their crops—if something goes wrong, it’s because they did something wrong, and they can’t blame it on the weather.Weak, limp, discolored or stretched stems are major symp-

toms that indicate one or more of the needs of your plants are not being met. Weak stems will not transport water and nutrients efficiently throughout the plant, greatly diminish-ing potential yield. They cannot support large leaves, fruit or flowers and can be damaged easily.Certain conditions affecting the overall health of the plant

tend to manifest themselves as afflictions of the plant stem. Most stem problems can be treated and all can be prevented, though—with a little knowledge and foresight.

The most common cause of weak or stretching stems is an inadequate source of light. When plants do not receive light of sufficient intensity for their growing phase they can begin to grow thin and spindly as they stretch towards the light source. The stems of plants left growing on the furthest edge of the range of a light source will often begin to reach toward the middle, and will be noticeably weaker than those directly under the light. This can be remedied a number of ways. Rotating the plants periodically so that they each get equal time directly under the light can help keep stems from stretching. Sometimes just adding reflective material—either mirrored or flat white—around the edge of the growing area can help to keep light in, or you can install an apparatus

called a light mover to move the light source around over the garden, effectively distribut-ing light evenly to all your plants.

Sometimes all your plants can begin to stretch. This is most likely because the light is simply not strong enough. Fast-growing plants in their vegetative stage require lights that can provide them with 2,500 lumens/foot candles of light for 18 uninterrupted hours a day in order to maintain vigorous health and strong stems. Flowering plants need 10,000 lumens/foot

candles of light for 12 uninterrupted hours

“Weak stems will not transport water and nutrients efficiently throughout the plant, greatly diminishing potential yield.”

strong steMs, heaLthy pLants

a day to produce fruit and flowers to their maximum potential.Each different wattage and type of bulb

will have a different output, and since light diminishes exponentially over distance, these two variables must be factored in when determining the right bulb for you and the correct distance to hang that bulb from in order to effectively light your plants. For exam-ple, plants growing two feet away from the light source are receiving four times less light than plants one foot away from the light source receive. To tell how much light in lumens your plants are actually receiving from the light source, divide the light output by the distance squared.Nitrogen is another factor that is

highly important in leaf and stem development as well as overall plant health. It is a macronutrient that plants need in relatively large amounts—although less so when fruiting or flowering. Nitrogen is largely responsible for the chloro-phyll in leaves, making it essential for photosynthesis, and also plays a signifi-cant role in the production of certain amino acids and enzymes.


When nitrogen reaches toxic levels within the plant, how-ever, certain adverse symptoms may become pronounced. Plants may appear overly green and lush, yet growth will be stunted and fruit may have trouble setting. Stems will be-come weak and can be easily damaged. They will also be able to be bent over with little resistance, and the tissue in the stem that transports water throughout the plant will begin to break down, restricting the uptake of water by the plant.There are a few causes of nitrogen toxicity. There could

be too much nitrogen present in the growing medium or hydroponic solution, in which case flushing the growing medium with straight pH balanced water or with a clearing solution can help rid the medium and plant of the built-up nitrogen. You should also use a quality plant nutrient for-mula like pine tree oil extract, which is a natural source of nitrogen and relatively safe compared to other nitrogen-rich nutrient additives because the risk of toxicity is low.There is another relatively common disorder that affects

the stems of plants during their seedling phase, known as Pythium wilt or damping-off. Seedlings that are afflicted will seem to rot at the point where the stem and the grow-ing medium meet. This is a fungal infection of the plant tis-sue that will eventually cause the stem to be unable to take

up water and nutrients from the roots, causing the seedling to eventually fall

over and die.

“Nitrogen is largely responsible for the chlorophyll in leaves, making it essential for photosynthesis.”


To prevent Pythium wilt from afflicting your seedlings, plant them in well-drained soil with plenty of light. If the air becomes too stagnant or humid, damping-off is likely to occur. Humidity domes can be used to keep the air and root zone humid while seedlings or cuttings grow, helping to prevent the fragile roots from drying out. Humidity domes should be ventilated or removed once a day for 10 minutes to allow the seedlings or cuttings to be exposed to some dryer air, thus reducing the risk of them damping-off.Using a sterile growing medium can also help

prevent Pythium wilt. To sterilize your own soil—this is best done in mid-summer—simply place it in a clear plastic bag and leave it in direct sunlight. The sun will heat up the soil, killing any harmful pests and bacteria. Soil can also be baked in an oven at 350°F for 10 to 15 minutes.Adding a layer of dry material along the soil line will help

to keep the surface dry and also reduces the likelihood of fungal growth. Sand, perlite or fine sphagnum moss is ideal for this.Once a couple of weeks have passed, plant stems will

toughen up enough for them to no longer be at risk of contracting the damping-off fungus.Another fungal infection that can cause stems to be weak

and droop is verticillium wilt. This disorder can affect plants in every stage of growth, although the symptoms of verticillium wilt will most often first appear on the lower and outer parts of the plant. Stems and leaves will become weak and begin to droop, and the interior of the stems may become discolored.Cleanliness is the best way to prevent verticilli-

um wilt. Thoroughly cleaning equipment between crop rotations can help, and sterilizing tools when taking cuttings is essential to prevent the spread of the fungus from one plant to another. This is important since plants are at their most vulnerable when being cut—with the stress involved, and the fact that there is an open wound created, through which the fungi could find easy access to the plant’s vital systems.

Keeping your grow room well ventilated and making sure plants are not spaced too closely together can also reduce the risk of verticillium wilt. There is no cure for this infection, so plants that are noticeably afflicted must be destroyed in order to prevent the transfer of the disease to the remaining healthy plants.There are a number of reasons your plant stems may

seem stretched or weak, although insufficient light inten-sity, nutrient toxicity and disease are the most common

culprits. Keep these factors in check and you’ll go a long way toward preventing plant stem problems from ever oc-curring—which will lead to generations of healthy plants with strong stems. MY

“Keeping your grow room well ventilated and making sure plants are not spaced too closely together can also reduce the risk of verticillium wilt.”



BEGINNER’S CORNER

BY Mike TaTTersall

»How toKILL Indoor Gnats


Gnats are commonly found in house-plants and are attracted to ripe fruit and vegetables in your kitchen. In fact, they are in the same family as fruit flies. To keep pesky gnats at bay, follow these simple guidelines.Houseplants that are infested with

indoor gnats need to be taken outside. Once outside, take off the top layer of soil and replace with new soil. Gnats breed in the soil, so once you remove the old topsoil, you are effectively eliminating the eggs that will otherwise become more hungry little gnats. Be sure not to overwater your houseplants, unintentionally creating the conditions that gnats love to breed.To kill the indoor gnats that are hang-

ing around your kitchen, there are several things you can do. First, place any fruit and vegetables inside your refrigerator and do not leave food on your counters. Food, especially fruit and vegetables that are left out in the open, are like a big, flashing welcome mat for

Gnats. these tinY Yet harMless insects are a coMMon pest nuisance inside the hoMe, especiallY durinG WarM Weather of sprinG and suMMer When conditions are ideal for their survival. While there MaY not be a WaY to avoid theM coMpletelY, You can treat the probleM once these uninvited Guests set up caMp in Your hoMe.

gnats. Simply put, gnats need food to survive. If you take it away, they will die.Be sure to

store your trash in a sealable container or within a cabi-net. If gnats can easily access the food located in your trash, they will continue to feed and thus stay happily satisfied in your home. Take the trash out regularly to keep the old food out of your home and away from tempting hungry gnats.To trap and kill persistent gnats that

are still indoors, fill a bowl with vin-egar. Gnats love the smell of vinegar and are attracted to it. Seal plastic wrap over the bowl and poke a few holes into the wrap, to create a trap for the

gnats. They will find their way into the vinegar but not be able to get out and will soon die. Refill the

bowl with new vinegar as needed.

Ammonia can be effective for keep-ing gnats away from

the drain in your kitchen sink where rotting food is likely

to be. Pour a little down the drain and do

not use your sink for a few hours so the scent is not washed away.Indoor garden stores sell sprays that are

specifically formulated to kill indoor gnats. Because these sprays contain pesticides, be extra cautious where you spray them and avoid spraying them in areas where food is served or consumed.(Source: www.howtodothings.com)

Maximum Yield USA | April 2011 77

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