Horticulture For The Properties Of Potting Mixes

Testing the physical properties of potting mixes

Discuss about the Horticulture for the Properties of Potting Mixes.

Activity -1

Testing the physical properties of potting mixes

Air-filled porosity (AFP)

Results

Name of mix	V (ml)	Vt (ml)	AFP%	Wettability time
1. Potting mix- 1	0.92	4.8	19%	25s
2. Potting mix-2	.75	5	15%	10s
3. Potting mix -3	1.25	5	25%	35s
4. Potting mix -4	0.9	4.5	20%	15s
5. Potting mix-5	1.5	5	30%	10s

Wettability

Results

Name of mix	Time	Comment
1. Potting mix- 1	25s	Wettability is normal
2. Potting mix-2	5s	The water holding capacity of this mix is very high
3. Potting mix -3	35s	Wettability of mix is very low
4. Potting mix -4	15s	Wettability is normal
5. Potting mix-5	10s	The water holding capacity of this mix is very high

Observations

Quality of the mixes

• The Air-filled-porosity of all the provided potting mixes shows an acceptable AFP score, which lies between 15 to 30% for all the plants. As per potting mix porosity provided by Department of agriculture and food, the count of at least 15% AFP is minimum for proper propagation (Agric.wa.gov.au, 2016).
• The wettability of potting mix also occurred between 10s-15s, time duration indicating a good water absorption capacity of potting mixes. The wettability of potting mix -2 is high because potting mix used for lettuce has high humus rich soil that holds water for the long duration.

Potential problems

• There is no potential problem because the obtained AFP is above 15% in all the potting mix samples.
• The wettability of potting mix-4 is very low.

Recommendation

• Wetting agent can be used to enhance the wettability of potting mix-4

Activity -2

Testing the chemical properties of potting mixes

1. pH

Results

Potting mix	pH-colour kit test	pH- pH meter test	EC- EC meter test
1. Potting mix- 1	5.4	5.3	5.3
2. Potting mix-2	5.6	5.6	5.6
3. Potting mix -3	3	3.1	3.1
4. Potting mix -4	5.6	5.7	5.7
5. Potting mix-5	5.9	5.9	5.9

Observations

a) Are the results for both methods of pH measurement the same?

The pH results using the colour test kit, pH meter and EC meter are not observed to be same in all tests. In the five potting mix there is a difference in the reading of pH using colour test kit from the reading of EC and pH meter.

The readings of EC meter and pH meter are similar in all the potting mix but the reading of colour kit test differs in the potting mix- 1,3 and 4. However, the readings of EC meter and pH meter are similar for all the five potting mix.

b) Which method, in your opinion, is more accurate and in which situation would you use each method?

In my opinion, the EC meter and pH meter can be considered as more reliable and accurate because the reading of both the instruments are same for all the five potting mix. Further, Quraishi et al. (2011) stated that pH meter simplifies the pH test where the pH value is determined automatically by the electronic device and displayed on the meter screen. In contrast, using a pH strip of the pH testing kit requires manual identification of pH that can persist manual errors. Hence, the pH meter is considered to be more accurate method to determine pH.

The pH colour kit is reliable when there is no requirement of identifying the specific pH value. The pH colour kit is best to identify only the acidic or basic nature of the sample. Whereas, pH meter and EC meter are best for a situation where a specific value of pH is required to be evaluated in the sample.

c) Compare your results with the Australian standard AS3743 and classify this mixes?

As per AS3743 there are four categories of potting mixes that are All-purpose potting mix, Acid-loving plant potting mix, Premium potting mix and plant-specific potting mix (Agric.wa.gov.au, 2016).

All the above provided potting mix can be considered as All-purpose potting mix because their physical conditions are suitable for all purpose of the plantation. However, potting mix- 3 can be considered as acid-loving plant potting mix because its pH value is slightly acidic then required for all-purpose plantation (Toogood, 1999).

Testing the chemical properties of potting mixes

d) Make a recommendation for the use of these potting mixes. (Are they suitable for any type of 
propagation or for the general plant growing purpose?)

The above provided potting mix – 1, 2, 4, and 5 are suitable for any type of propagation but the potting mix – 4 is suitable for propagation of plant that requires acidic soil for growth.

e) If the mixes don’t comply with the standard, please give the recommendation how to adjust these 
mixes, so they can be suitable for propagation purpose.

All the potting mixes are suitable for all-purpose propagation except potting mix - 4 that has an acidic pH. This potting mix can be made suitable for propagation by adding NaOH solution and reducing the acidity of mix below 6.5 to make it usable for all types of propagation (Mason, 2004).

Activity -3

1. The toxicity test

Results

Potting mixes	Roots after 4 days (mm)
1. Potting mix- 1	3mm
2. Potting mix-2	1.3mm
3. Potting mix -3	.2mm
4. Potting mix -4	2mm
5. Potting mix-5	2.3mm

Observation

As per above performed toxicity test, all the potting mixes seedling showed some amount of rooting but the seedling in potting mix-4 showed very less growth of just. 2mm. The reason for low rooting in seeds of potting mix-4 can be the acidic nature of this mix because Quraishi et al. (2011) studies state that acidic soil does not supports propagation resulting in slow growth or even seed death.

However, all the other potting mix are suitable for propagation because there is rooting observed between 1.3-3mm within 4 days duration. The potting mix-1 shows maximum propagation capacity with rooting of 3mm within 4days.

Activity -4

Propagation techniques

Plant record

Plant name	Trial date	Treatments	Hormones
Lilly pilly (Syzygium smithii)		Cleaning with running tap water for 15 min and soaking in 70% alcohol for 1 minute. Rinse the plant with running tap water after alcohol treatment.	IBA hormone to stimulate root growth
Lettuce (Lactuca sativa)		Soaked in boiling water for 48 hours.	Abscisic acid for stimulating growth
Pumpkin (Cucurbita pepo)		Soaked in boiling water for 48 hours.	Ethylene for growth
Lemon (Citrus limon)		Soaked in boiling water for 24 hours.	Cytokinin (BAP) for growth
Azalea (Rhododendron azaleas)		Cleaning with running tap water for 15 min	IBA hormone to stimulate root growth

*All the treatments and hormones are added as per requirement of provided plant sample

Quality of propagation material

Propagation material of plants	Quality analysis
Lilly pilly – shoot cutting	The shoot cuttings were healthy, new shoots, disease free with no mechanical damage. They were little contaminated with regular dust and water.
Lettuce - Seeds	Seeds provided were having ASA (Australian Seeds Authority Ltd.) certification. Seeds were disease free, healthy and test certified material.
Pumpkin - Seeds	Seeds provided were having ASA (Australian Seeds Authority Ltd.) certification. Seeds were disease free, healthy and test certified material.
Lemon - Seeds	Seeds provided were having ASA (Australian Seeds Authority Ltd.) certification. Seeds were disease free, healthy and test certified material.
Azalea – Shoot cuttings	The shoot cuttings were healthy, new shoots, disease free with no mechanical damage and contamination.

Other comments

Plant -1

The shoot cutting sample of Lilly pilly plant was treated with running tap water and 70% alcohol because it consisted dust and outside water contamination. The treatment with 70% alcohol allows complete purification from dust with no damage to plant sample.

The hormone IBA Indole-3-butyric acid was used to initiate rooting in the provided shoot cutting because shoot cutting needs to hold the soil as quickly as possible.

Plant -2

Lettuce seeds provided as a sample were soaked in boiling water to make swell seed up to 1.5 larger sizes that will make germination very quick and easy in propagation. The abscisic acid is used to initiate seed germination and growth.

Plant -3

Pumpkin seeds were soaked in boiling water for 48 hours to induce germination and ethylene worked as a growth hormone to initiate quick germination and shoot generation.

Plant – 4

Lemon seeds were soaked in boiling water for 24 hours to induce germination and BAP hormone 6-Benzylaminopurine worked as shoot generation hormone.

Plant -5

Azalea shoot cuttings were washed with running water for 15 minutes to avoid chances of contamination and IBA was added in the mix to initiate rooting in the provided sample (Hartmann et al. 2011).

Propagation techniques

As these are two types of propagation materials that are shoot cuttings and seeds for all the five plants. Therefore, the seed germination and stem cutting propagation techniques are used to perform propagation.

Seed propagation

Materials

• Seed sample
• Boiling water
• Pots or trays 3inches deep with base holes
• Potting mix
• Flat board
• Saltshaker
• Spatula
• Peat moss
• Water
• Hormones

Method

• Taken the seed sample and performed the treatment process as described above for each seed sample.
• Taken pots and trays soaked in 10% Clorox solution. The pots and trays were washed thoroughly.
• Filled the pots and trays with potting mix to the top and loosen the potting mix with flat board about half inches below the top of the pots.
• Further, the treated seeds were added to the surface mix with a spatula and shacked with saltshaker.
• Covered the seeds to the depth of twice their diameter.
• Peat moss or potting mix was used to cover seeds
• Added the required amount of hormone specific for each sample.
• Regularly water the by keeping the container in the pan of water for 1 minute that allows mix soak up the maximum water (Quraishiet al. 2011).

Shoot propagation

Materials

• Shoot cuttings sample
• Running tap water
• 70% alcohol
• Pots or trays 3inches deep with base holes
• Potting mix
• Sharp knife
• Rooting gel
• Forecep
• Peat moss
• Water
• Hormones

Method

• The shoot cuttings were treated as per the treatment mentioned above. Using a sharp knife, a cut was made on the bottom of shoot samples at 45-degree angle to increase rooting area. Keep 2-3 set of leaves attached while cut the bottom set of leaves.
• Further, the prepared cutting was dipped in rooting gel that contains required rooting hormone.
• Taken pots and trays soaked in 10% Clorox solution. The pots and trays were washed thoroughly.
• Filled the pots and trays with potting mix to the top and loosen the potting mix with the flat board about half inches below the top of the pots.
• Now hold the shoot with the help of foreceps and place it straight in potting mix pots.
• Kept the inoculated plant in the warm and bright place.
• Provided water and hormone as required by the sample (Al Khateeb et al. 2012).

Results and observations after weeks of propagation

Successful propagation data

Propagation plants	Success rate	Quality
Lilly pilly – shoot cutting	Good shooting and rooting	Healthy growth
Lettuce - Seeds	Good roots but fewer shoots	Retarded shoot growth
Pumpkin - Seeds	Good shooting and rooting	Healthy growth
Lemon - Seeds	Good shooting but less rooting	Retarded root growth
Azalea – Shoot cuttings	Good shooting and roots	Healthy growth

Rooting quality

Propagation plants	Treatment	Hormone	Rooting quality	Rooting rate
Lilly pilly – shoot cutting	70% alcohol + IBA	IBA	Healthy roots	80%
Lettuce - Seeds	Soaked in boiling water	Abscisic acid	Healthy roots	94%
Pumpkin - Seeds	Soaked in boiling water	Ethylene	Healthy roots	68%
Lemon - Seeds	Soaked in boiling water	Cytokinin (BAP)	Retarded roots	30%
Azalea – Shoot cuttings	70% alcohol + IBA	IBA	Healthy roots	90%

*The rooting rate was calculated by determining the percentage of plants showing roots

As per above observations, Lettuce sample propagation showed less shooting and lemon sample showed less rooting. The reason can be applied hormones where changing the shooting hormone for lettuce can initiate shooting process and implementing rooting hormones for the propagation of lemon seeds can initiate better rooting process. Using ethylene in place of abscisic acid can provide better shooting in lettuce. Further, using IBA in seed propagation of lemon can provide better rooting rate. The propagation obtained for Lilly, Pumpkin and Azalea were satisfactory.

References

Books

Hartmann,HT, Kester,DE, Davies,FT, & Geneve,RL 2011, Plant Propagation Principles and 
Practices, Prentice Hall, Sydney

Mason,J 2004, Nursery Management, Land Links, Collingwood, Australia

Toogood,A 1999, Plant Propagation, DK Publishing, INC, London

Journals

Al Khateeb, W., Hussein, E., Qouta, L., Alu’datt, M., Al-Shara, B. and Abu-Zaiton, A., 2012. In vitro propagation and characterization of phenolic content along with antioxidant and antimicrobial activities of Cichorium pumilum Jacq.Plant Cell, Tissue and Organ Culture (PCTOC), 110(1), pp.103-110.

Quraishi, A., Jadhav, S.K. and Gupta, S., 2011. In vitro Clonal Propagation of Cassia tora L.(Coffee Pod): A Medicinal Plant. Biotechnology, 10(6), pp.546-550.

Websites

 Agric.wa.gov.au. (2016). Potting mixes | Department of Agriculture and Food. [online] Available at: https://www.agric.wa.gov.au/nursery-cutflowers/potting-mixes [Accessed 12 Jul. 2016].