2.Growing Media Flashcards
Explain considerations when growing plants in containers.
- Restricted root volume
- Water retention and supply
- Drainage - Must have hole in pot
- Nutrient availability - correct amounts must be added as roots can not go in search for them
- Stability of compost – crumb structure needs to withstand constant wetting
Why is soil not suitable for use with pot plants?
- The crumb structure will not allow for constant watering
- Pore space collapse and oxygen supply is restricted
- May contain weeds seeds/ pest and disease
- Variable unknown amount of nutrients
- Variable PH level
Peat alternatives?
- Coir (coconut fibre)
- Garden compost
- Wood based – bark sawdust paper etc
- Locally available materials such as straw wool etc
State the effects of growing acid-loving plants in alkaline soils.
- Calcifuges
- Stunted growth
- Lime-induced chlorosis
- Nutrient availability decreases which may result in deficiencies
Name a situation for each different type of compost.
Multi-purpose composts
- Wide range of uses - low nutrient levels
- Raising seed, container planting
Ericaceous
- Lime free and suitable for Calcifuges
- Planting of Rhododendron
Seed composts
- First planting of seeds, low in nutrients as high levels would be harmful and could even prevent germination
- Good aeration and good moisture retention
Cuttings composts
- They require a high air-filled porosity
- A good mix - 50% of organic material such as composted bark and 50% of an opening material to provide good drainage such as perlite, coarse sand or grit
Advantages and disadvantages of using peat?
Advantages –
- Light, cleaner to handle and easy to store
- Sterile - does not need sterilising
- Consistent
- Good open structure with good drainage/water retention capabilities
- Weed, pest and disease free
Disadvantages –
- Non renewable product, develops very slowly
- As the compost is light the staking of tall, heavy plants can be problematic
- It is often very difficult to re hydrate when dry
Advantages and disadvantages of loam-based compost?
Advantages:
- Useful for plants that are to be in containers long term, such as shrubs, as it is very stable
- They have a high level of buffering which means they avoid fluctuating water and nutrient content
- Clay content of loam provides a longer supply of nutrients
- The weight of the loam provides stability for the container. Therefore good for outdoors as less likely to be blown over.
- Sterile loam used to prevent fungi and disease
Disadvantages:
- It’s hard to get a good quality loam to use as a base
- The weight does make the it difficult to move containers and not suitable for hanging baskets
- Expensive - needs to be sterilised
- Peat is often used - Non-renewable
Advantages of loamless compost?
Advantages:
- Soilless - so do not need to be sterilised
- Light weight
- Cleaner to handle
- Cheaper – no sterilising
- Often no peat used
Describe the characteristics of 4 distinct named types of growing media (excluding garden soil) used for plants in containers.
Coir based
- Lightweight
- High water-holding capacity with good porosity and air content
- pH neutral
- Low nutrient content
- Sustainable - waste product
Wood based
- Excellent drainage
- Low PH
- Suitable for potting seeds and growing plants on
Local authority green waste
- High nutrient content
- High PH
- Best used as a mulch
Composted bark based
- Bark is non-clumping with an open, stable structure and is well aerated
- Low water-holding capacity
- Variable pH value
List 4 distinct problems associated with growing plants in containers.
- Plants can become root bound
- Containers can become difficult to move if they are large /blown over if the container is not heavy enough
- Permanent plantings require top dressing or repotting
- Plants need to be watered
Identify 2 situations where growing plants in containers is more suitable than growing them in open ground.
- Tender plants can be placed in the correct situation for sunlight/shade, etc.
- Ericaceous plants can be grown in a growing media with a suitable pH
- Containers can be moved to avoid excess rainfall/frost etc
- Application of nutrients can be controlled when feeding plants
What are the ingredients of loam-based seed compost?
- 2 parts by bulk medium loam (partially sterilised)
- 1 part bulk peat or peat substitute
- 1 part by bulk sand
What are the ingredients of potting compost?
(for growing on)
- 7 parts bulky medium loam (partially sterilised)
- 3 part bulk peat or peat substitute
- 2 part by bulk sand
What are the ingredients of ericaceous compost?
- 2 parts by bulk loam (partially sterilised)
- 1 part by bulk peat or peat substitute
- 1 part by bulk sand
List the benefits of adding organic matter to a soil
- Increased activity of micro organisms
- Hummus is added - Soil structure improved (aeration/drainage)
- Water holding capacity improved
- Nutrients in soil are gradually increased