Introduction
This carnival was started around June 2004 by the Ngee Ann Polytechnic. This is the first time I am doing this project, and I think it is going to be interesting. I have a group of 5 members, including Phillip (me), Kamesh, Sheng Hui, Kai Sheng, Jia Hao.
Objective
The objective is to grow the largest sunflower (in diameter).
Daily 'chores'
- Shifted our plants to where most sunlight is located.
- Add artificial fertiliser.
- Took records of our plants (pH value of soil, Amount of light in Lux and Temperature in degrees celcius, the height of the plants will be taken by our teacher.)
Research
My group surfed the net, and actually found great sites in relation to sunflowers and its growing conditions.
Growth Development
- Emergence will take 4-5 days when planted an inch deep (2.54cm) in warm soil, but will take a few days longer in cooler soils or when planted deeper.
Growing sunflowers
- Sunflowers generally grow best on well-drained soils.
- They perform comparatively well on sandy loam soils.
Planting
- Sunflowers should be planted 1 to 1 1/2 inches deep (around 2.5 to 3cm).
- Planting sunflower can begin anytime after soils have warmed to 50 degrees F.
Fertility
- Sunflowers respond to nitrogen.
- On sandy soils, sunflower is often responsive to extra potassium fertilizer.
- Sunflower appears tolerant of soils with a pH down to 5.5, but consider liming if the pH is below 6.0, to improve nutrient availability in the soil.
Weed control
- Weeds must not be allowed to get a head start on sunflower.
- Weeds can be controlled either through herbicides or tillage.
Insects
- As the plant grows, many insects feed on sunflower foliage, including grasshoppers and caterpillars.
- The real stage to be scouting for insect pests is once the flower bud has begun to develop.
- Head clipper insects which attack the stem right below the head can cause the whole head to fall off, but are uncommon.
- Main threat to sunflowers is sunflower moth or banded sunflower moth.
- The adult moths should be identified through scouting, and if present in sufficient numbers, should be sprayed before larvae become established; Once the eggs have hatched and larvae have moved inside the head and seeds, insecticide control is very difficult.
Diseases
- In cool wet soils, seeds or seedlings may be attached by fungi, so seeds are typically treated with fungicide.
- Various leaf and foliar diseases will cause surface spots or yellow patches.
- Probably the greatest disease threat to sunflower is sclerotinia (white mold).
Changing the pH value of soil
- Like mentioned, The soil pH value directly affects nutrient availability.
- Conifers thrive best in acid soils (pH 5.0 to 5.5) while most ornamentals do best in slightly acidic soils (pH 5.8 to 6.5). Our sunflowers should belong under the "ornamentals" group, which means we need our soil to have a pH value of 5.8 - 6.5.
- In highly acid soils, aluminum and manganese can become more available and more toxic to the plant.
- Also at low pH values, calcium, phosphorus and magnesium are less available to the plant.
- At pH values of 6.5 and above, phosphorus and most of the micronutrients become less available.
Factors affecting soil pH
- The pH value of a soil is influenced by the kinds of parent materials from which the soil was formed.
- Soils developed from basic rocks generally have higher pH values than those formed from acid rocks.
- Rainfall also affects soil pH. Water passing through the soil leaches basic nutrients such as calcium and magnesium from the soil. They are replaced by acidic elements such as aluminum and iron. For this reason, soils formed under high rainfall conditions are more acidic than those formed under arid (dry) conditions.
Increasing soil pH (making it alkaline)
- To make soils less acidic, the common practice is to apply a material that contains some form of lime.
Selecting a liming material:
There are 4 choices of ground limestone: pulveized, granular, pelletized and hydrated.
1. Pulverized lime is finely ground.
2. Granular and pelletized lime are less likely to clog when spread with a fertilizer spreader over turf areas, the finer the grind of the limestone the faster it will change the soil pH value.
3. Hydrated lime should be used with caution since it has a greater ability to neutralize soil acidity than regular limestone.
- Wood ashes:
1. Wood ashes can be used to raise the soil pH. They contain small amounts of potassium, phosphate, boron and other elements.
2. Ashes should not come in contact with germinating seedlings or plant roots as they may cause damage.
3. Avoid using large amounts of wood ashes because excessively high pH values and subsequent nutrient deficiencies may result.
Decreasing soil pH (making it acidic)
- Two materials commonly used for lowering the soil pH are aluminum sulfate and sulfur.
- Aluminum sulfate will change the soil pH instantly because the aluminum produces the acidity as soon as it dissolves in the soil.
- Sulfur, however, requires some time for the conversion to sulfuric acid with the aid of soil bacteria.
- If any of these materials are in contact with plant leaves as when applied to a lawn, they should be washed off the leaves immediately after application or a damaging leaf burn may result.
Click here to know about...
- Problems encountered
- Some insects which feed on sunflowers
- Sunflower growth check (POT and GARDEN)
- Records table (where I recorded the parameters)
Credits
Special thanks to:
- Ngee Ann Polytechnic, which held this competition.
-`Suppiah Kameshwara, Lee Kai Sheng, Teo Jia Hao and Toh Sheng Hui; My team members for the competition.
- Mr Eugene Joseph Simon; My Science teacher who helped me out in data logging and taking pictures of our sunflowers.
- Miss Dominic Tan; Teacher-in-charge.
- "http://www.jeffersoninstitute.org/pubs/sunflower.shtml" for the information on sunflowers.
- "http://hgic.clemson.edu/factsheets/HGIC1650.htm" for the information on soils.