Whether containers are used indoors or outdoors for growing plants, the key to their success is understanding their special needs. Container plants need careful watering. Outdoor containers and baskets will probably need daily watering during summer months, even in overcast weather, as they dry out very quickly. Check the compost (potting soil) regularly as it can be difficult to wet once it has dried out. Adding water-retaining granules or gels to the compost before planting will help to reduce the frequency of watering. For indoor plants, too much water can be as bad as too little.
Most potting composts contain only food sufficient enough for six weeks (on average) of plant growth, after which the plants will slowly starve unless other food is introduced into the container. Slow-release plant food granules added to the compost when planting will ensure that the plants receive adequate nutrients throughout the growing season. Other plant foods, such as liquid feeds, need to be applied fortnightly.
While standard potting compost is suitable for all purposes, container compost, which is especially formulated for containers and hanging baskets, contains extra fertilizer and moisture-retaining granules. Lime-hating plants, such as heathers and camellias, must be grown in compost which contains no added lime.
Container plants are readily available, but if you want to use a lot of them in your displays, they can be expensive. One way of having a plentiful but cheap supply is to grow the easier ones yourself from seed. Sooner or later young seedlings will need re-potting as they don’t thrive in large pots. Divide the plants, if necessary, and replant them in pots the same size as the ones in which they were previously grown.
Part of the fun of container gardening is experimenting with the different planters available. Garden centers stock an increasing variety of styles. Junk shops, car boot sales and flea markets are also worth a visit.
1. Traditionally, hanging baskets are lined with sphagnum moss. This looks very attractive and plants can be introduced at any point in the side of the basket. As sphagnum moss does tend to dry out faster than other liners, it is advisable to use a compost (soil mix) containing water-retaining gel.
2. Coir fibre liners are a practical substitute for moss. Although not as good to look at, the coir will soon be hidden as the plants grow. The slits allow for planting in the side of the basket.
3. Cardboard liners are clean and easy to use. They are made in various sizes to fit most hanging baskets. Press out the marked circles on the cardboard liner if you wish to plant into the side of it.
Planting in Pots
1. Cover the base of the container with a layer of coarse gravel or polystyrene (plastic foam) to help with drainage. Add a layer of compost (soil mix) until the container is about half full.
2. When sowing large seeds, such as sunflowers, use a (libber, cane or pencil to make holes for each seed. Plant the seeds and then firmly tap the side of the pot using the flat of your hand to fill the holes with compost.
3. When planting a full plant, arrange the plant inside the container and place compost around it to hold it in position. Add additional compost to the container until it is level with the rim, then firm it around the plant.
4. Cover the surface with more compost if necessary, then water the container and remove any air-pockets around the plant’s roots. Add a top layer of coarse grit, to act as a mulch.
Container-grown plants can be enhanced by the choice of pot used. Remember this is not a low-maintenance option as the plants will not be able to draw as much nourishment or water from the surrounding soil.
Some plants are very easy to sow from seed. Sunflowers rarely disappoint, even if you are a complete beginner. Whether sowing large or small seeds, water the pot using a fine hose on a watering can, or by standing the pot in a saucer of water until the surface of the compost is moist. Cover the pot with a black plastic bag as most seeds germinate best in a warm dark place. Check daily and bring into the light when the seedlings are showing.
Fill the pot with seed compost (soilmix). Gently firm and level the surface by pressing down on the compost using a pot of the same size.
When sowing small seeds they should be thinly scattered on the surface of the compost and then covered with just enough sieved compost to conceal them. Firm the surface using another pot and then treat in the same way as large seeds.
Sooner or later plants need re-potting in order to accommodate their new size.
1. Seedlings will probably be ready to move into larger pots when the roots start to emerge through the holes in the base of the pot. To check, gently remove the root ball from the pot and if there are plenty of roots showing, you will know the plants are ready for a move.
2. If there is more than one seedling in the pot, gently break each seedling away with a good rootball. (Some plants hate to have their roots disturbed. The information on the seed packet will tell you this. These seeds are best sown individually in peat pots.)
3. Lower the rootball of the plant into the pot and gently pour compost around it, lightly pressing the compost around the roots and stem. It doesn’t matter if the stern of the seedling is buried deeper than it was previously as long as the leaves are well clear of the soil. Water using a can with a fine hose.