Greenhouse Growing Media and Plant Fertilization

1. Greenhouse Growing Media and Plant Fertilization Mr. Wilson Greenhouse Uintah High School

2. Unit Objectives • Examine the components and properties of growing media. • Describe the components of growing media. • Describe the functions of growing media. • Determine desirable properties of growing media. • Evaluate the advantages and disadvantages of soilless media. • Investigate chemical characteristics of growing media. • Interpret pH test results of a growing media sample.

3. Additional Objectives • Supply nutrients to greenhouse crops. • Explain plant nutrition. • Describe pH and how it is modified. • Describe the components of a fertilizer. • Explain the methods of applying fertilizers to horticulture crops. • Demonstrate proper techniques for sampling growing media. • Test and determine pH level of various growing media.

4. TERMS • Aeration – the presence of air • Growing medium – material used for plant growth • Hydroponics – growing plants w/o “soil” • Leach – to remove by percolation • Pore spaces – voids for water or air holding • Soil – outer layer of the earth suitable for plants • Soilless medium – sterile product/s used for plants

5. What is growing media? The material that your plants grow in is called the “growing medium. Characteristics: • Soil-less mix – usually doesn't contain soil • Used to grow greenhouse and nursery plants • Usually is pasteurized • Usually purchased or made

6. Functions of Growing Media Growing medium has three main functions • 1) Supply roots with nutrients, air, and water. • 2) Allow for maximum root growth. • 3) Physically support the plant. Anchor roots! Roots grow in the spaces between individual particles of soil.  Air and water also travel through these pore spaces.  Water is the medium that carries nutrients that plants need to fuel their growth, and air is needed for root growth and the health of soil microorganisms that help supply plants with nutrients.

7. Advantages of Soil less Mixes • sterile • lightweight • good moisture retention and drainage • free of weed seeds Designed for the plant type!

8. Disadvantages of Soil less Mixes • light weight - pots tip in strong wind • minor elements are missing • transplants may not adjust well to new media

9. Which Makes the Best Growing Medium? • Sand • Peat Moss • Field Soil • Vermiculite • Pearlite • Water • Gravel

10. What are the types of growing media used in greenhouse production? • Is “soil” used? • Soil – the earth’s outer crust is full of life! • Bacteria • Fungi • Invertebrates

11. What are the negatives of using “SOIL” for containers? • Unknown history of: • Pesticides • pH • Fertility level • High shrink / swell • Soil shrinks as it dries – forming cracks • Higher disease probability

12. So what media should you use? • Sand? Dries to quickly. • Peat moss? Dries to slowly. • Choir? Hard to get wetted. • Water? To little air. • Pearlite? To much air. • Vermiculite? Pricey. • Potting soil mixes? Just right.

13. What effect does growing media have on plant growth? • Supplying Nutrients • Some media cannot hold essential elements for plants. Nutrients are leached out to rapidly. • Stressed plants are prone to disease and insect damage – increasing loss. • Reduced growth = lower returns

14. What effect does growing media have on plant growth? • Supplying Air • As air is reduced, plant stress increases. • Roots need oxygen and water – both in moderation. • Increasing stress increases pest susceptibility and profit loss

15. What effect does growing media have on plant growth? • Uniformity • Large scale production demands that all plants perform equally. • This is only possible if all plants get equal inputs from a uniform media.

16. Content of commercial mixes • Soilless mixes contain various combinations of the following materials.

17. Perlite • improves aeration • of volcanic origin

18. Spahgnum Moss • Dehydrated remains of acid bog plants • Used to cover seeds because it is lightweight, controls disease, and holds moisture.

19. Peat Moss • Partially decomposed underwater vegetation. • Holds moisture well • Low in nutrients

20. Vermiculite • Exploded Mica • Improves aeration • Holds moisture very well

21. Limestone • Raises pH • You would not want to use this in our area’s natural soils.

22. Plant nutrients and fertilizers Plants do not eat! Not Food! • Water • Elements

23. Water • Water is the most important plant nutrient • Makes up 90% of the plants weight • Water transports the other elements around the plant

24. Elements • divided into two groups, macro and micro • Major elements (macro) • Nitrogen – N • Phosphorus – P • Potassium - K

25. minor elements (micro) • Calcium - Ca • Magnesium - mg • Sulfur - S • Iron - Fe

26. minor elements (micro) • Manganese - Mn • Boron - B • Copper - Cu • Zinc - Zn

27. Plant requirements • large amounts of major elements • relatively small amounts of minor elements

28. A way to remember the Nutrients required for plant growth. • C.B.HOPKiNSCaFeMighty good • Closed Monday Morning See YouZen! • Other elements for plants? Not essential but help plant growth:Se, Ni, Co, Na??

29. Commercial fertilizers • shows % or pounds per cwt. (100#) of the three major elements in large numbers on the container or bag.

30. Commercial fertilizers • 5-10-5 • 5% N, 10% P, 5% K • remaining 80% is filler • NP&K are always listed in that order.

31. Soil tests • determine amount of elements needed for various plants. https://www.youtube.com/watch?v=3YuA20kZ1EA

32. How to take a soil sample • Take random samples from the area to represent the area you want to test. • Mix all samples together. • Take a sample from the mix of about 16oz of soil. • Complete soil test info sheet. • Mail to a reputable lab. • Analyze results and make decisions.

33. Nitrogen • has most noticeable effect on plants • encourages above ground vegetative growth • regulates use of other elements

34. Too much Nitrogen • lower disease resistance • weaken stem because of long soft growth • lower fruit quality

35. Too much Nitrogen • delay maturity • increase winter damage to plants

36. Not enough Nitrogen • yellow or light green color • stunted root and top growth

37. N lost easily from soil • leaching - being filtered down through soil with water • not held by soil particles, dissolved in water • O.M. holds insoluble N for slow release

38. Nitrogen Deficiency in Corn

41. Phosphorous • held tightly by soil particles • not easily leached

42. Phosphorous • effects plants in several ways • encourage cell division • flowers and seeds don’t form without it • hastens maturity, offsetting quick growth caused by N.

43. Phosphorous • encourage root growth • makes K more available • increase disease resistance • improves quality of grain, root and fruit crops

44. Insufficient P • purple color on underside of leaf • reduced flower fruit and seed production

45. Insufficient P • susceptibility to cold injury • susceptibility to plant diseases • poor quality fruit and seeds

49. Potassium • modifies both fast soft growth of N and early maturity of P • is essential

50. Potassium • increase disease resistance • encourages healthy root systems • essential for starch formation