roots, such as those on Monstera deliciosa and some Philodendrons, to help them to remain soft, pliable, and active.6 Avoid spraying plants when they are in strong, direct sunlight; water droplets may act as lenses and burn the leaves.
7 Regular misting helps to discourage red spider mite infestation.
Repotting Houseplants
Eventually, most houseplants (except those grown for their short-term display) fill their pots with roots and need to be transferred to slightly larger ones. A plant left in the same pot will slowly deteriorate. When selecting a new pot, check the following.
The new pot is clean, dry, and about 1in (25mm) larger. When a plant is already in a large pot, perhaps 6in (15cm) or more wide, the new pot can be 2in (5cm) larger.
When repotting into a clay pot, put a piece of broken clay pot (known as a crock), concave side downward, in the base to prevent the drainage hole from becoming blocked. This is unnecessary when repotting into plastic pots; these are usually filled with peat-based compost, which is more fibrous and less likely to fall out of the smaller drainage holes into the base.
Use the same type of compost in which the plant is already growing.
Step-by-Step Repotting
1 The day before repotting, thoroughly water the compost and allow the excess to drain. This is essential since a plant with a dry root ball will not rapidly become established in a new pot.
2 Place the fingers of one hand over the top of the root ball and invert it, together with the pot. Sharply tap the rim on a hard surface (without damaging the plant’s leaves), so the pot and root ball separate.
3 Fill a suitable pot with compost to about one-third of its depth and press to lightly pack it. (Add a crock in its base first if it is a clay pot.)
4 Without damaging the root ball, position it in the center of the pot. Check that the top of the root ball is about ½in (12mm) below the new pot’s rim. Add or remove compost.
5 Keep the plant and root ball upright and carefully dribble fresh compost around it. Gently pack it until just covering the root ball. When repotting a plant in a large pot, leave a slightly larger space between the compost’s surface and rim.
6 Stand the plant on a well-drained surface and gently water the compost from above, without unduly disturbing it. A couple of waterings may be necessary. Watering from above also helps to settle fresh compost around the root ball.
7 Stand the pot on a clean saucer or place it in a cachepot. Initially, position the plant in light shade for two to three days, or until established.
Use a cachepot or place the pot on a saucer after repotting.
Feeding
To remain healthy, plants need a balanced diet throughout their lives. For most, this is provided by compost in a pot, with the addition of regular feeding or, for plants in large pots, top-dressing. Regular feeding makes a remarkable difference, and there are three main ways to do it.
Liquid fertilizers are the traditional, easiest, and most widely used choice for feeding houseplants. Concentrated fertilizers are diluted in clean water and applied to potting composts. First read the instructions and add the correct amount to clean water. Agitate and apply to moist compost. Many bromeliads have urns at their centers (resembling small vases formed by leaves); keep these topped up with water, and add weak liquid fertilizer, usually from spring to late summer.
Fertilizer pills and sticks are more recent innovations. They are pushed into the compost to provide food for several months. They are best used in spring and up to midsummer. If they are used in late summer, they provide food when some plants are resting. Unfortunately, unlike liquid feeding (which encourages the development of roots throughout the compost), pills and sticks concentrate nutrients in one position, resulting in an uneven spread of roots.
Foliar feeds are ideal for houseplants that can absorb nutrients through their leaves. Air plants are normally fed in this way. Plants rapidly respond to foliar feeding, and the technique is best used as a tonic for plants with smooth, non-hairy leaves. Avoid spraying flowers or using foliar feeds when plants are in strong sunlight. Strong foliar feeds will burn the leaves.
Remember that not all houseplants need feeding at the same frequency throughout the year. While most are fed during summer, not all need feeding in winter (see the plant directory in Part Two for details). Before feeding a plant, check that the compost is moist; this decreases the risk of roots becoming burned by strong chemicals and helps spread plant foods throughout the compost.
Feeds that are too strong soon damage roots, so it is essential to adhere to the manufacturer’s instructions. To avoid root damage, it is better to provide a plant with a weak liquid fertilizer than one that is too strong.
Dilute liquid fertilizer in water and stir.
Apply liquid fertilizer to moist compost.
Grooming and Supporting
Grooming keeps houseplants attractive throughout their lives. Flowering houseplants need to have dead flowers removed, while others need to be supported or have their leaves cleaned. When removing dead flowers and leaves, put them into a bag and throw them away; do not scatter them around a plant, because decaying pieces of plants are unsightly and encourage the presence of diseases.
Insert a fertilizer stick into the compost.
To prevent fertilizer from going all over the place when you foliar feed plants, simply place the plants in a plastic bag.
Add weak liquid fertilizer to a bromeliad’s central urn.
Top-Dressing Large Houseplants
Instead of being repotted, large plants are usually top-dressed.
Use a small trowel to carefully remove the surface compost without damaging the roots. The depth of the compost that is removed is usually no more than 1in (25mm).
Add slow-release fertilizer to fresh compost and use it to top up the pot so its surface is about ½in (12mm) below the rim. Then, carefully water the compost using a watering can with a rose.
Cleaning Leaves
