RHS Level 2 R2104

Question 1

What is meant by the term seed?

Answer 1

A seed is developed as a result of sexual reproduction from an ovule which becomes the seed.

Question 2

Benefits to plant of sexual reproduction.

Answer 2

Allows variation and adaption to the environment.

Question 3

Horticultural benefits of propagating plants from seed?

Answer 3

Produces variation for which new cultivars can be produced.
It's the only method for some species.
Can get large numbers from each plant.
Easily stored.
Can avoid virus transmission

Question 4

Limitations of propagating from seeds?

Answer 4

Some seed is difficult to germinate.
Some plants may not produce viable seed.
Lack of uniformity
Time to maturity
Some seeds don't store easily.
Hard to handle fine seed.

Question 5

Name some plants usually propagated by seed…

Answer 5

Nigella damascena
Daucus carota
Phaseolus vulgaris

Question 6

Main horticultural uses of seed…

Answer 6

Vegetable production
Bedding plant production
Annuals
Lawn seed

Question 7

What is meant by seed viability?

Answer 7

Seeds which contain a living embryo and will germinate when conditions are right.

Question 8

Requirements for seed germination:

Answer 8

Moisture- water content needs to be about 70% for full chemical activity to begin. Continuous supply is needed if germination is to proceed at a steady rate. Too much will exclude air.
Temperature - Influences activity of enzymes. species dependant between 0 and 40
Oxygen- little oxygen can impose dormancy until more air is supplied.
Light/dark - Some species inhibited from germination by light, others need light to germinate.

Question 9

What is dormancy? Three explanations…

Answer 9

A period of little activity other than very slow rate of respiration.
A seed is said to be dormant if the environmental conditions are suitable for germination and the seed is viable but it does not germinate.
Dormancy is a method of controlling the germination of the seed until conditions are IDEAL for both germination AND plant growth.

Question 10

Name parts of a seed….

Answer 10

Testa
Plumule
Radicle
Cotyledons
Hilum
Micropyle
Hypocotyl - external
Epicotyl - external

Question 11

In a seed what is the testa

Answer 11

Outer coat, protects the seed and embryo,.

Derived from the outer layers of the ovule.

Question 12

Describe the plumule and radicle

Answer 12

Plumule is the embryonic stem, made up of stem tip and a few leaflets.
Radicle is the first/primary root, made up of root tip and first root hairs.

Question 13

What is a cotyledon?

Answer 13

Seed leaf. Dicots have two, monocots have one. Food structure of seed.

Question 14

What is the hilum and micropyle?

Answer 14

The hilum is the scar from where the seed was connected to the fruit.
The micropyle is a minute hole at the end of the scar where the male gamete entered the ovule to fertilize it.

Question 15

Describe the Hypocotyl and the Epicotyl.

Answer 15

Hypocotyl is the short length of stem BELOW the cotyledon.

Epicotyl is the short length of stem ABOVE the cotyledon.

Question 16

Describe physical dormancy. Example

Answer 16

Usually caused by the testa which can be very hard and impervious to water and gases.
The testa needs breaking down to allow water and oxygen through.
They can be broken down in the soil by bacteria and fungi over a few months.
Lathyrus odorata

Question 17

Describe physiological dormancy.

Answer 17

An internal dormancy where the embryo needs to undergo some changes before it can germinate.
Some seeds need to go through a period of after ripening.
E.g. washing out/breaking down of inhibitors from the seed.

Question 18

Breaking dormancy - what ways?

Answer 18

Stratification - seed mixed with damp sand, put in a box/container, in a cool place over winter. Can speed up the process by using a refrigerator. Breaks physiological dormancy.

Scarification- wearing away or chipping part of the testa.
Small scale by rubbing or filing with file or sandpaper.
Commercially done by putting seed through emery paper rollers until testa is worn very thin.

Chipping/nicking - use sharp knife to create a hole in testa to allow oxygen and water in.

Question 19

What is germination?

Answer 19

The emergence of the radicle through the testa, usually at the micropyle.

Question 20

Describe the stages of the germination process.

Answer 20

1) uptake of water
2) increase in the rate of respiration in embryo
3) breakdown and mobilisation of food store
4) rapid cell division
5) testa splits
6) radicle emerges

Question 21

What is hypogeal germination?

Answer 21

The cotyledon remains BELOW the soil surface.
The Hypocotyl will remail below the surface and the Epicotyl will elongate to come above the surface.
The plumule will emerge with the tip bent over for protection then will straighten out and grow towards the light.
E.g Vicia faba

Question 22

What is epigeal germination?

Answer 22

The cotyledons come above the soil level.
As the seed germinates and grows the Hypocotyl elongates and pushes the cotyledons above ground.
Once above the soil level the epicotyl will elongate and the first leaves will appear.
E.g. Phaseolus vulgaris.

Question 23

What is meant by orthodox seed, give examples.

Answer 23

Orthodox seeds are dry seeds which need to be stored under cool, dry conditions.
E.g. Nigella damascena, Daucus carota, Phaseolus vulgaris.

Question 24

What is meant by Recalcitrant seed, give examples.

Answer 24

Recalcitrant seed is moist/fleshy and requires short term cool moist storage.
e.g. Quercus robur, Acer palmatum

Question 25

Storage factors, of seed, affecting germination

Answer 25

To slow down rate of respiration to prevent seed using up food reserves.
Length of time - 3-5 years. Viability decreases with age.
Temperature- low 4oc
Seed moisture content - low humidity 4% - 6%

Question 26

Describe the prep of fleshy fruits for seed storage with example…

Answer 26

Solanum lycopersicum

1) harvest when fully ripe
2) maceration- squash into seive
3) separation - place in water and leave for 3 days, seeds will separate at bottom
4) clean in a seive
5) dry in a cool place

Question 27

Describe method for sowing fine seed with example, including container, growing media and aftercare.

Answer 27

Begonia semperflorens.
Prepare a seed tray with seed compost by over filling it and swipe off the top using a striking off board or edge of hand. Use a firmer to press down soil equally. Water before sowing using a fine sprinkler.
Mix the fine seed with dry silver sand and hold seed mixture in one hand and broadcast the seeds with the other over the surface of the soil making sure to distribute evenly.
Do not cover as they need light to germinate.
Aftercare:
Keep tray in a humid environment but not too moist to cause rotting or disease.
Provide light, but keep turning tray if light is from one direction.
Can cover with glass or polythene but shade from direct sunlight.

Question 28

Describe method for PRICKING OUT fine seed with example, including container, growing media and aftercare.

Answer 28

Begonia semperflorens.
Once seedlings are large enough to be handled.
Water before pricking out.
Prepare new containers, individual modules or a tray containing potting compost, mixture of organic matter and grit/vermiculite.
Tap the seed tray lightly to loosen the seedlings.
Ease the seedling out of the tray gently using a spatula holding the seed leaves.
Make a hole in the new tray using a dibber.
Place seedling in the hole so seed leaves are just above compost and firm into place. Repeat, keeping seedlings in a straight line and evenly spaced.
Aftercare:
Put trays/modules into greenhouse or polytunnel at a suitable temperature and water them to settle in using fine rose spray.

Question 29

Describe method for POTTING OFF fine seed with example, including container, growing media and aftercare.

Answer 29

Begonia semperflorens.
Same as pricking out but put into individual pots.
Fill pot halfway with potting compost.
Seedling is then placed in the centre and compost placed around the roots to the top of the pot.
Remove surplus soil and tap pot to settle compost around the roots.

Question 30

Describe method for sowing, pricking out and potting off of medium seed with example, including container, growing media and aftercare.

Answer 30

Lactuca sativa (lettuce).
Same as fine seeds but no need to mix seed with sand.
Broadcast 2-3mm apart or 2-3 seeds in each cell of module.
Lightly cover with sieved soil.
Press with firmer and water from bottom or finely from above. Label it.
Place seed tray in a warm environment 12-15oc. Can cover tray with sheet of glass until germination to keep moist.
Pricking out as per fine seed.

Question 31

Describe method for sowing, pricking out and potting off of large seed with example, including container, growing media and aftercare.

Answer 31

Cucurbita pepo (courgette).
Sown individually in cells or small pots.
Prepare container with seed compost, overfilling then striking off and firming down. Water the prepared tray.
Hold the seed and push it down into the soil and cover it over.

Question 32

How can you avoid pest and disease problems after sowing seeds?

Answer 32

Use clean water for watering. Not from a water butt.
Hygiene is important:
Use clean containers
Sterile growing media
Surrounding area should be kept as p&d free as possible.
Avoid over watering which can lead to dampening off.
Avoid crowded seedlings.

Question 33

What aftercare should be done for seeds and seedlings?

Answer 33

Don’t over water but keep moist.
Keep optimum temperature constant. Bottom heat can be used.
Create a humid environment.
Good oxygen supply.
Use a propagator or cover with glass/polythene or place in a polytunnel/greenhouse.
Keep even lighting by placing in greenhouse or polytunnel. If in a window keep turning tray.
Keep out of direct sunlight

Question 34

Aftercare techniques for young plants….

Answer 34

Transplanting- more air, light, nutrients and moisture
Watering/ misting- maintain water levels to prevent stress or wilting.
Reduced humidity
Ventilation- to prevent dampening off, maintain constant temperature
Shading - prevent scorching and temperature fluctuations.
Feeding - move to new compost or use tonics.
Hygiene
Hardening off - to let plants adapt slowly to final growing position
Pricking out - to give plants more space and nutrients.

Question 35

Describe the ground preparation of an outdoor bed for seed sowing.

Answer 35

1) remove any weeds by physical or chemical methods. Hand, hoeing etc…
2) dig over the bed to loosen soil and ensure there is no hard layer beneath the seed, incorporating any organic matter if required.
3) before sowing need to produce a fine tilth to sow into.
Use a fork to break up clumps of soil and remove stones.
4) rake the soil and level out sowing area.
5) firm down the soil depending on soil texture, especially if lots of air has been introduced to the soil by digging.
6) rerake if firming has been carried out.

Question 36

Describe the method for sowing seeds in drills in open ground using a named example.

Answer 36

Daucus carota.
After preparing the bed for sowing,
1) Mark the rows - using marker canes at both ends of the rows at correct spacing. Carrot rows should be 15cm apart.
2) string lines fitted around the markers.
3) take out the drills using a trowel or corner of rake along the string line. Make v shaped drills.
4) water the bottom of the drill.
5) sow the seed thinly into the drills 10-12mm deep
6) cover the seed with soil
7) firm the soul over the seeds gently
8) water.

Question 37

Describe the method for sowing seeds by BROADCAST in open ground using a named example.

Answer 37

Lolium perenne (grass seed mixture)
After preparing the bed ( usually a lawn)
1) broadcast the seed on the soil surface at 25-50g/m2
Can be done by hand by taking a handful of seeds and throwing it forward across your body propelling seed out with an even spread. Or via a fertiliser distributor.
2) rake over the soil and water in.

Question 38

Describe the method for sowing seeds by STATION SOWING in open ground using a named example.

Answer 38

Pastinaca sativa (parsnip)
Prepare bed for sowing
1) Mark the rows - using marker canes at both ends of the rows at correct spacing. Parsnip rows should be 30cm apart.
2) string lines fitted around the markers.
3) take out the V shaped drills using a trowel or corner of rake along the string line.
4) water the bottom of the drill.
5) sow the seed in stations, sowing 3-4 seeds at intervals of 7-10cm, 1cm deep.
6) cover the seed with soil
7) firm the soul over the seeds gently
8) water.
9) will need to thin to 1 per station at a later date

Question 39

Describe the method for sowing seeds in a TRENCH or FLAT bottomed drill in open ground using a named example.

Answer 39

Pisum sativum (pea)
Prepare bed for sowing
1) Mark the trenches - using marker canes at both ends of the rows at correct spacing. Pea trenches should be 45cm apart.
2) string lines fitted around the markers.
3) Create a shallow trench 5cm deep, 5cm wide along the stringline.
4) water the bottom of the trench
5) sow the seed 5cm apart in a zig zag formation along the trench.
6) cover the seed with soil
7) firm the soil over the seeds gently
8) water.

Question 40

Describe the method for sowing seeds INDIVIDUALLY in open ground using a named example.

Answer 40

Phaseolus vulgaris.
Prepare the bed for sowing.

1) Mark the rows - using marker canes at both ends of the rows at correct spacing. Runner beans should be 60cm apart.
2) string lines fitted around the markers.
3)
4) Make holes using a dibber 15cm apart and sow 2 seeds per hole 5cm deep.
5) cover the seed with soil
6) firm the soil over the seeds gently
8) water.
9) thin out to one seedling per cane.

Question 41

When should you sow Daucus carota outside? Describe the aftercare once sown….

Answer 41

April to early July.
Can cover with fleece or mesh to help prevent carrot fly.
Water when dry.
Weed around the seedlings.
When seedlings reach a suitable size thin out to 1 every 5cm.
Continue weeding in between plants.

Question 42

When should you sow Pastinaca sativa outside? Describe the aftercare once sown….

Answer 42

March until early may.
Can cover with fleece or mesh to help prevent carrot fly.
Water regularly when dry.
Weed around the seedlings.
When seedlings reach a suitable size thin out to 1 at every station.
Continue weeding in between plants.

Question 43

When should you sow Lolium perenne outside? Describe the aftercare once sown….

Answer 43

Sow when the soil is warm and plenty of moisture, mid spring and early autumn.
If dry water the area with a sprinkler to keep moisture levels up.
Can cover with fleece or netting to stop birds eating the seed.
Once seedlings reach 5cm high, lightly refirm the soil.

Question 44

When should you sow Pisum sativum outside? Describe the aftercare once sown….

Answer 44

March until July.
No thinning needed.
Weed around the seedlings.
Water regularly.
Can cover with mesh or netting to protect from birds and other animals eating the seed.

Question 45

When should you sow Phaseolus vulgaris outside? Describe the aftercare once sown….

Answer 45

End of may into June.
Thin to one seedling per cane.
Weed around the seedlings.
Water regularly.

Question 46

Describe the harvesting of Phaseolus vulgaris.

Answer 46

Harvest seeds from plant which is true to type and pest and disease free and undamaged.
Harvest pods which are ripe, late summer/early autumn.
The pods should contain fully formed seeds.
Harvest seeds in dry weather.

Question 47

Describe the separation and cleaning of collected Phaseolus vulgaris seeds

Answer 47

Carefully separate seeds from the pods.
Retain the fully ripe and undamaged ones.
Grade the seeds and reject ones which are too small.
Dry any wet seeds for 7-10 days on paper.
Check for disease lesions on the seed coat.

Question 48

Describe the storage and packing of collected Phaseolus vulgaris seeds

Answer 48

Place seeds in dry paper bag or envelope.
When fully dry store in plastic box with silica gel.
Keep in frost free, cool, dry conditions.
Long term can be kept in a refrigerator in sealed container.

Question 49

Describe methods of avoiding diseases when sowing seeds.

Answer 49

Use sterile clean equipment.
Use clean mains water, not from a butt.
Use fresh sterile growing media.
Ensure seed is from a good source from non diseased plants.
Avoid wet waterlogged soil conditions.
Sew seeds at suitable density which is not too thick.