How to grow native and naturalised Trees from seeds

           Native and

           Naturalised

Many species of trees can be grown from seeds sown in October. Children love to engage in collecting and sowing seeds, especially when the importance of their task is explained to them. They are amazed that they can set in progress something that can outlast them for hundreds of years.

Oak

Requirements

Seeds of some of the following trees:oak, beech, hazel, rowan, ash, sycamore, hawthorn, blackthorn, crab apple, horse chestnut. These should be collected from healthy trees which are not grown in isolation.

Note that some seeds have special requirements for germination.

Seed compost, comprising of a half and half mixture of peat/coir and horticultural sand.

Potting compost.

Half litre and litre sized empty milk cartons or 15 cm wide pots.

Old slates or clear plastic.

Self-adhesive labels.

A container filled with wet moss for temporarily storing seeds.

Different Trees and Seeds

Hazel and Beech

Half litre cartons are ideal for these seeds also. The method of sowing is the same as above.
Hazel and beech nuts however must be left outside to be subjected to the cold.
They can be taken inside in the spring when they have germinated.

Crab and Sycamore

The pips of crab apples and the seeds of sycamores can be sown in yogurt cartons, small pots or cell trays using a seed compost.
Leave them outside.
When the seedlings are large enough to handle they can be transplanted to 6 cm pots filled with potting compost.

Ash

Collect Ash keys (seeds) as soon as they are ripe. Sow the seeds immediately in half-litre cartons filled with a growing mixture which must contain some lime (one seed per carton).

Some good soil must be mixed with the sand and peat in equal parts.

Cover the seeds lightly, water them and leave the containers outside. Some will germinate in the first spring but most seeds will need two winters outside, to break their dormancy.

Hawthorn, Blackthorn, Rowan

Start off by leaving the berries in plastic bags for a few days. The flesh will begin to rot. Remove the rotting flesh from the seeds by washing them under a tap.

The hard-coated seeds of these trees need to be subjected to cold conditions before they will germinate.

Some seeds will germinate after the first spring, but most will need the cold of two winters before this will happen. This is referred to as stratification or vernalisation.

Definitions

Coir: A peat substitute made from crushed coconut shells. If it is not available at your local garden centre, it may be ordered.

Horticultural sand: This is sometimes called silver or granite sand. It is used on golf courses and in children's play-pits. All garden centres stock it.

Native: tree species that predate human settlement in Ireland. Proof of their growth has been found in pollen samples preserved in peat, e.g. hazel, ash, oak, birch, holly.

Naturalised: tree species that have been introduced to Ireland in modern times and successfully reproduce without human interference, e.g. sycamore, horsechestnut.

Storing seed: Wet moss prevents acorns, chestnuts and beech mast from drying out. These lose their viability if they become dry.

Start Here

1. Litre sized milk cartons are ideal for oaks and horse chestnuts. These should be well-washed.

   Small holes are pierced in the bottoms with a knitting needle or skewer. Then place about 3 cm of sand in each container, for drainage purposes.

2. Fill the cartons almost to the top with potting compost.
    
3. Insert the acorns and horse chestnuts into the moist compost. (One nut per carton). They should be sown at a depth of roughly twice their own size and covered. The pointed sides of the acorns should face upwards.

Continue...

1. Water the cartons well and label them as follows:
   Name of tree, Date of sowing, Child's name.
    
2. Place the cartons outside in a cool, sheltered frost-free corner of the grounds. They will succeed too if they are left on window-sills in the coldest part of a school.
    
3. If they are left outside it's a good idea to protect them from mice by placing slates over them.

   If they are kept indoors plastic should be placed over them to prevent them from drying out.

After Care

1. The cartons should be checked regularly to make sure the compost is moist.
    
2. In March the seeds will germinate. Keep them indoors or outdoors in the cartons until autumn when they can be inserted in a nursery bed.

   Place them in rows 30 cm apart and with 15 cm between plants.

Nursery Bed

Next Autumn

1. The following autumn transplant the plants again, with 30 cm between them.
   This encourages the growth of healthy fibrous roots.
    
2. When they are about 60 cm high they can be planted in their final positions.

A glass or plastic cover prevents evaporation and keeps the compost moist. This saves the bother of watering. It also keeps cats and mice away from the trays.

Pots and Seeds

Separate pots should be used for each type of seed.

Only moist horticultural sand (play sand) should be used in pots.

About four measures of sand to one measure of seed is the recommended ratio.

The Process

1. Some drainage material, such as small stones should be placed in the bottoms of the pots. Cover these with moist sand, half-filling the pots.
2. Place a layer of seeds is on top of the sand. Cover the seeds with more moist sand almost to the tops of the pots. ( A pot can contain several layers of seeds but it is easier to work on one layer later on). Alternatively, the seeds can be mixed through the sand without bothering with layers.
3. Cover the pots with mesh and leave them outside in a cold place.
4. When the warm weather comes they can be buried in the ground to prevent them from drying out. It is wise to put a marker where they are buried!

After Care

1. The following spring (after sowing the seeds) the pots can be inspected to see if some germination has occurred. Any sprouting seeds should be transplanted to small pots of potting compost.
2. In the second spring after sowing, there should be mass germination. The sprouting seeds should be transplanted as above.
3. In autumn, the young trees can be inserted in a nursery bed.

Text:Patrick Madden
Illustrations:Eileen Fleming
Editor / Photographs:Marian Rollins
Web Page Design:Taran Pyper 2013