Catch the winter sun
Growing vegetables and herbs in containers or going vertical are ways to use limited winter sun, writes Alice Spenser-higgs
AS WINTER approaches the changing angle and position of the sun can plunge previously sunny areas into shade. As most winter herbs, veggies and flowers are sun lovers, making use of the sunspots becomes one of the challenges of winter gardening.
The first resort is containers, and provided they are sheltered from cold draughts and receive plenty of sun, they can be extremely productive.
One can grow broccoli, baby cabbage, baby carrots, rocket, spinach or Swiss chard, loose leaf lettuce and Asian greens, such as mizuna, pak choi, tatsoi and red giant mustard in containers.
Perennial herbs — thyme, rosemary, winter savory, oregano, parsley, chives — can be planted with the vegetables or on their own and mixed plantings can be brightened up with edible winter flowers such as calendula, violas and nasturtiums.
If you opt for a container garden on a balcony, bear in mind the weight of containers filled with soil, plus your weight. Terracotta pots look great but they do get very heavy! Space is also an issue, so choose compact, upright growing veggies.
Containers must have drainage holes and be wide and deep enough. Carrots and lettuce do well in a deep trough-like container. A large, wide container planted up with four to six Swiss chard Bright Lights or Red Giant mustard or a mix of the two can be a very attractive feature.
Pak choi, tatsoi and mizuna would probably be best planted on their own in containers as they can develop into quite substantial plants. The same applies to the Brassicas, and having them in individual containers also makes it easier to meet their specific water and nutrition needs.
The other important consideration is the growing medium. Do not use garden soil because it becomes too compact and doesn’t drain well enough.
Commercial potting soil doesn’t contain nutrients so it should be mixed with superphosphate and a slow-release organic fertiliser like Vita-Veg (6:3:4). Mixing in palm peat or vermiculite improves water retention.
Check the containers daily. The soil should be moist and never dry out. Foliar feed with a liquid fertiliser at half strength once a week. This is especially important for Brassicas — which includes the Asian vegetables — because they are heavy feeders.
Cover the surface with a light mulch of leaves or peanut shells. This protects the roots and the soil life. Regular watering with a watering can may compact the soil and mulch prevents this. It’s a good idea to use a soft nozzle on the watering can or hose.
Another option is vertical gardening, especially if you have sunny north facing walls.
These can be as simple as stackable modules, geotextile planters with deep pockets or the VertiGarden, which is an enclosed growing module with built-in irrigation. The system comes from the UK and has been used at both the Chelsea Flower Show and the Hampton Court Flower Show.
VertiGarden modules can be linked together and the irrigation joined to form a single system. Being an enclosed system with virtually no evaporation, water requirements are minimal, between five to 10 minutes a day, depending on the temperature and position of the VertiGarden.
It is suitable for shallow-rooted herbs and salad leaves, as well as strawberries. Pansies, violas, petunias and other winter flowers work just as well, especially if one wants to make a feature of a wall.
One seedling is planted per cavity and for the first two or three weeks the modules are kept flat until the plants are established. The modules are then mounted on a sunny wall.
The brackets supporting the module can be screwed directly into the wall but it is more advisable to mount them onto wooden blocks, especially if the bricks are rough.
Having the brackets so firmly in place makes it easy to take down the modules when the plants are over, replant and replace. Essentially, the VertiGarden becomes a permanent fixture.