Houseplant Handbook. David Squire
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Step-by-Step: Sowing Seeds
1 If only a few seeds are to be sown, use a small, shallow pot, but a plastic seed tray is better for larger numbers. Fill it with seed compost and use your fingers to pack it, especially around the edges.
2 Place more compost in the seed tray and use a straight-edged piece of wood to level it with the rim. Then, use a flat-surfaced piece of wood to pack the compost to ½in (12mm) below the rim so the seeds can be lightly covered and watered without water spilling out.
3 Tip a few seeds into a piece of light-colored, stiff paper folded into a V-shape. Then gently tap its end to distribute seeds evenly over the surface, but not within ½in (12mm) of the edges.
4 Use a flat-based horticultural sieve to cover the seeds in seed compost to about three times their thickness. Alternatively, use a culinary sieve.
5 Shallowly fill a bowl with clean water and stand the seed tray in it until moisture seeps to the surface. Remove and allow excess water to drain.
6 Cover the seed tray with a clear plastic lid to prevent the compost’s surface from drying out and to help maintain a somewhat warm temperature. Wipe the inside of the cover every day to remove condensation. Remove it entirely when seedlings germinate and small seed leaves can be seen.
Taking Cuttings
Many houseplants can be increased from cuttings. There are several different types of cuttings, but most important is that they should be healthy and free from pests and diseases.
Step-by-Step: Stem-Tip Cuttings
Each cutting is formed of a piece of stem, several leaves, and a terminal shoot. They are usually 3–4in (7.5–10cm) long and, if possible, taken from the outer parts of a mother plant, where they have received good light and are growing healthily and robustly.
1 Use a sharp knife to sever a healthy shoot close to the parent plant (do not leave a short stub).
2 Also use a sharp, clean knife to prepare the cutting, slicing just below a leaf-joint. Then cut off the lower leaves.
3 Fill a small pot with equal parts moist peat and sharp sand and pack it to ½in (12mm) below the rim. Use a small dibber to form a hole into which the stem can be inserted about 1in (25mm) deep. Pack the compost around the stem and lightly water from above.
4 Insert 3–4 short split canes into the compost and cover with a plastic bag. Use an elastic band to secure the bag around the pot. When shoots develop, remove the bag. Later, when growing robustly, transfer the rooted cutting to another pot.
Step-by-Step: Leaf-Stem Cuttings
Leaf-stem cuttings resemble stem-tip cuttings, but without the tip. This is an excellent way to increase plants with long, trailing stems that have leaves at regular intervals. Examples include both variegated and all-green forms of Hedera helix (Common Ivy).
1 Select a long, healthy stem from a mother plant and sever it just above a leaf. Do not use old, hard stems.
2 Cut the stem to form several cuttings; cut just above a leaf so that each cutting is formed of a leaf and piece of stem about 1 ½in (36mm) long. The stem part can be shortened if it is too long.
3 Fill a pot with equal parts moist peat and sharp sand and pack to ½in (12mm) below the rim. Use a dibber to insert 3–4 cuttings in each pot, each ¾—1in (18–25mm) deep, spaced out but not less than ½in (12mm) from the pot’s side. Pack compost around their bases and gently water from above.
4 Insert 3–4 short split canes into the compost and cover with a plastic bag secured around the pot with an elastic band. When shoots develop, remove the bag. Cuttings can be separated and repotted individually, but to produce a display more quickly just repot the entire pot of cuttings into another pot.
Step-by-Step: Leaf-Petiole Cuttings
Often used to increase Saintpaulia ionantha (African Violet), this involves cuttings formed of a leaf and a small stalk (petiole).
1 Form each cutting by severing the stem of a healthy leaf at the base of a mother plant, but avoid leaving short spurs or stems.
2 Use a sharp knife to trim back stems to about 1 ½in (36mm) long.
3 Fill a small pot with equal parts moist peat and sharp sand; pack to ½in (12mm) below the rim. Dip the end of each cutting in hormone rooting powder and use a small dibber to insert it so the base of the leaf is just above the compost. Pack compost around the stem and lightly water from above. Several cuttings can be inserted in each pot and transferred to individual pots when they develop small shoots.
Step-by-Step: Whole-Leaf Cuttings
Large-leaved begonias, such as Begonia rex (Rex Begonia) and Begonia masoniana (Iron Cross Begonia), can be increased by this method or the one following (leaf-square cuttings).
1 The day before taking cuttings, water the mother plant so the leaves are full of moisture. Select a healthy leaf and sever its stem just above the plant’s base.
2 Invert the leaf and use a sharp knife to sever the stem close to the underside of the leaf.
3 Cut across the main veins on the leaf’s underside with a sharp knife, positioning cuts ¾–1in (18–25mm) apart. Do not cut completely through the leaf.
4 Fill a seed tray with equal amounts moist peat and sharp sand; pack it to ½in (12mm) below the rim. Place the leaf on the compost vein-side downward and lightly press it down, holding in position with a few pebbles (or use U-shaped pieces of wire).
5 Put a plastic cover over the seed tray and place in gentle warmth. Keep the compost lightly moist.
6 Later, when small plants develop from the leaf’s surface, these can be moved to individual pots.
Step-by-Step: Leaf-Square Cuttings
1 Cut a healthy leaf from a parent plant and sever the stem close to the leaf’s underside. Position the leaf upside down and cut it into 1 ¼in (3cm) square pieces. Each must have several veins.
2 Fill a seed tray with equal parts moist peat and sharp sand; pack to ½in (12mm) below the rim. For each leaf cutting, use the blade of a knife to form a slit about ½in (12mm) deep in the compost’s surface. Push the side of a cutting (which was nearest to the leafstalk) into the slit and pack compost around it.
3 Insert other leaf cuttings—not within ½in (12mm) of the edge—and gently water from above without disturbing the cuttings. Allow excess moisture to drain, then cover with a plastic dome.
4 When young shoots develop from each cutting, transfer them to individual pots.
Step-by-Step: Leaf-Triangle Cuttings
This is another popular way to increase large-leaved houseplants. As with leaf-square cuttings, several new plants can be produced from one leaf.
1 Cut a healthy leaf from a parent plant and sever the stem close to the leaf’s underside. Leave the leaf upside down and cut it into triangles, which tend to be longer than the squares of leaf-square cuttings. These can be inserted deeper into the compost, which helps