FLORICULTURE CDE. Identifying and Controlling Plant Disorders

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1 FLORICULTURE CDE Identifying and Controlling Plant Disorders

2 Nutritional and Environmental Disorders

3 Poor soil drainage Problem: Garden soil may appear ideal for potting indoor plants but actually causes problems. This soil may be wonderful for outdoor gardening under natural conditions, but after a few months the garden soil becomes hard and almost rock-like in a plant pot. Plants in garden soil grow satisfactorily for a month or two, but soon the lower leaves turn yellow and the plants become unthrifty. This problem is the result of poor drainage and the lack of soil aeration due to improper soil structure. Most garden soils become compacted with time and house plants grow poorly in compacted soil. Solution: A proper soil mixture is of utmost importance to a house plant because the roots are restricted by the pot. A good potting soil should have the capacity to retain some air and moisture and yet drain well and hold nutrients. Sand or perlite added to the soil will improve aeration and drainage. Clay or organic matter will help retain water. Organic matter, plus commercial fertilizers, will maintain adequate nutrient levels. Modern "soilless" potting medias do not contain soil so the addition of fertilizer is required to provide all essential plant nutrients.

4 Pictures of poor drainage

5 Overwatering Problem: Plants that have been over watered often have similar signs to plants that have been under watered. An over watered plant will be droopy, wilty looking, with leaves hanging as if weighed down. The roots of the plant are drowning; unable to breathe the air that they need to support the plant. The roots become weak and start to rot. Solution: When the soil or the compost has become too wet or saturated, the leaves of the plant will become limp. Disease can over take a plant quickly when it is in this vulnerable state. The lower portions of the plant are the first to become infected, so you might have to cut a few leaves off if you find this happening to your plant. For the plant that has become too wet and moist, take the plant and soil out of the container in which it was sitting. Hold the plant firmly in your hand so it will not break or be damaged while you are working with it. A plant with lots of roots will retain the shape of the container when you first pull it out. The next step is fairly easy, you are going to take a few paper towels and set the plant on them. Allow some of the excess water to drain out of the soil and into the paper towel. Pat down the soil to bring more water out. Check the roots for fungus, bacteria or worms that may be taking over in the soil. Leave this over watered plant to sit out on a few fresh paper towels over night. Excess water will continue to drain out of the soil and the roots will have a better chance of getting the air that it needs for reviving itself. After a day, or at least twelve hours, you can put the plant back into the container. Add a little fresh soil if need be around the edges and the top of the plant. Allow the plant to dry out normally before watering once again.

6 Overwatering Pics

7 Too little water Problem: Droopy plants, leaves falling off, shriveled up, light colored soil Solution: Soak in water until it perks up then water regularly. Cut off any completely damaged foliage

8 Inadequate lighting Problem: Inadequate lighting will cripple your plants and may leave lasting developmental damage even after lighting conditions are improved. The stems will be spindly and elongated, causing them to have difficulty supporting your plants as they grow. Fewer leaves may develop and the leaves that do grow will not expand to their normal size. As the plants mature, they will not be able to flower or bear fruit and may even turn yellow depending on the length of the lighting deficiency. Solution: Move to an area with filtered light. Turn plant to straighten out tropism.

9 Too much Light Problem: Plants can suffer from sunburn! These are common symptoms of excessive light: Dry patches on leaves. If the site gets hot enough, buds and flowers may drop off and the entire plant may wilt. Solution: Cut off sunburn and move plant to a place with more shade or filtered light

10 Improper Temperature Problem: Sudden loss of leaves is frequently caused by a rapid temperature change. It may also be caused by such factors as prolonged hot or cold drafts, dry air, exposure to gas or furnace fumes or by changing the location of the plant from a sunny to a dark location. Solution: Move plant away from all these factors.

11 Nitrogen deficiency Problem: Nitrogen (N) deficiency in plants can occur when woody material such as sawdust is added to the soil. Soil organisms will utilize any nitrogen in order to break this down, thus making it temporarily unavailable to growing plants. It is more likely on light soils and those low in organic matter content, although all soils are susceptible. Cold weather, especially early in the season, can also cause a temporary shortage Symptoms include poor plant growth, leaves are pale green or yellow in the case of bracs. Lower leaves show symptoms first. Leaves in this state are said to be etiolated with reduced chlorophyll. Flowering and fruiting may be delayed. Solution: Prevention and control of nitrogen deficiency can be achieved in the short term by using grass mowings as a mulch, or foliar feeding with manure, and in the longer term by building up levels of organic matter in the soil. Sowing green manure crops such as grazing rye to cover soil over the winter will help to prevent nitrogen leaching

12 Iron Deficiency Problem: A deficiency in the soil is rare but iron can be unavailable for absorption if soil ph is not between about 5 and 6.5 A common problem is when the soil is too alkaline (the ph is above 6.5). Also, iron deficiency can develop if the soil is too waterlogged or has been overfertilised. Elements like calcium, zinc, manganese, phosphorus, or copper can tie up iron if they are present in high amounts. Iron is needed to produce chlorophyll, hence its deficiency causes chlorosis. Symptoms include leaves turning yellow or brown in the margins between the veins which may remain green, while young leaves may appear to be bleached. Fruit would be of poor quality and quantity. Solution: Iron deficiency can be avoided by choosing appropriate soil for the growing conditions. Plants should be kept far away from cement. Iron sulfate or sulfur can be added to acidify the soil

13 Phosphorous deficiency Problem: Phosphorus (P) deficiency is a plant disorder that is most common in areas of high rainfall, especially on acid, clay or poor chalk soils. Cold weather can cause a temporary deficiency. All plants may be affected, although this is an uncommon disorder. Symptoms include poor growth, and leaves that turn blue/green but not yellow oldest leaves are affected first. Fruits are small and acid tasting. Phosphorus deficiency may be confused with nitrogen deficiency. Undersides of tomato plant leaves, and the veins and stems, may turn purple. Solution: It can be controlled by applying organic sources of phosphorus such as rock phosphate or a high-phosphorus fish fertilizer applied as a soil drench or foliar feed.

14 Salt damage Problem: Accumulation of salts. A white, flaky material on the soil surface of potted plants is often observed one to several months after potting. These are mineral salts that accumulate in the soil. Well water contains varying amounts of dissolved salts, as does the fertilizer you apply. With continuous watering, these dissolved salts accumulate in the soil and appear on the soil surface. Solution: The salts can be flushed out of the soil from time to time to prevent salt injury to your plants. Leaching (rinsing) the soil of most house plants every three to six months is a good cultural practice and will reduce the accumulation of salts in the soil. Clay pots which have accumulated salts should be soaked in hot water for 24 hours before reuse.