Landscape gardener and Life columnist Justin answers your questions.

I have two raised vege beds each 2m x 1m. If I follow seed manufacturers' instructions for spacing I can't fit much in. I often plant seeds/seedlings a bit closer than is recommended so I can grow all the different things I want. I'd like to know more about square foot gardening - specifically how far apart you can plant veges using this method and if it will help me fit more in. I'm currently growing caulis, broccoli, broad beans, parsley and Florence fennel, and will be planting lettuce, beetroot, snow peas and capsicum in the weeks and months to come.

- Mary Wilson

Square foot gardening is an excellent way to maximise space in a small garden and at the same time grow a variety of crops. Essentially, as the name suggests, square foot gardening requires you to divide your garden up into square foot portions, then plant each one in a different crop. Use the crop rotation system - legumes, leafy greens, fruits and roots in that order. Some gardeners plant a variety of plants in each square but I prefer to mass plant each square in a single crop because I find it easier to keep track of the crop rotation cycle. Square foot gardening encourages diversity and reduces pests and disease. In your case I would look carefully at whether growing broccoli and cauliflower is worthwhile considering how much precious space those plants take up and the relatively small yields they provide for the time taken to grow. In a small garden I would tend to focus on flavours like herbs and peppers and fast-growers like leafy greens and beans. Make the most of climbing frames as a vertical approach can double your harvest.

We have a problem garden bed which has poor drainage. It gets some afternoon sun, but is shaded by a cherry tree. We'd like to establish a low shrub hedge with scented flowers. Can you recommend anything?

- David

To improve the drainage, top dress the soil with gypsum then mulch heavily, but be careful not to pile mulch up the trunk of the tree. This needs to be done every year. Place cardboard under the mulch each time to keep the weeds down. The mulch will break down and enhance the soil, markedly improving your gardening prospects. For a low scented hedge two options spring to mind. Firstly gardenia "Professor Pucci" makes a sweet smelling addition to any garden. It is dense enough to form an informal hedge but may not respond well to continuous trimming. My first pick though would be Trachelospermum jasminoides or star jasmine which is usually grown as a climber or ground cover. It is an extremely versatile plant which can be trained and trimmed into any shape you want, including a low hedge.


Why is my parsley going yellow? It has been growing on a pot on the balcony for about a year and last month we added two more plants with some fertiliser pellets. But now both the old and the new plants are yellowing too. I've tried over-watering and under-watering, what else should I be doing? My pots of mint and sage are doing great.

- Nikki

It sounds like all the plants in that pot are suffering from a classic case of too much loving, aka fertiliser burn. In this case you may need to remove the plants from the existing pot and replace the soil. Parsley doesn't need much feeding but irregular watering can weaken your plants and make them susceptible to mealy bug attacks although this is uncommon.

Veggie garden
* Transplant young seedlings from the nightshade family such as chilli peppers, tomatoes and aubergine from trays into small pots. This will give them more space to develop and enable you to continue protecting them from spring winds and the occasional rogue frost.

* Prepare the ground for aubergine, chilli, tomatoes and potatoes by first adding gypsum to improve the tilth of the soil. Next add plenty of sheep pellets, blood and bone and a small amount of potash. Avoid using composts with large pieces of bark or sticks still incompletely decomposed. These "carbonic relics" will promote fungal infections as they decompose, such as black spot and blight.

* Leafy greens can go directly from the tray to the garden but make sure you protect against the slug and snail army. I use a ring fence of scrunched-up bird netting or set up traps such as an upturned bucket or bird-friendly slug pellets. The soil for leafy greens should be nitrogen rich so add plenty of compost and sheep pellets. Better still, plant leafy greens after a legume crop such as beans or peas, which fix nitrogen to the soil.

* Sow annual herbs such as basil and coriander in trays. If you're just sowing your herbs now, you have time to sow a green crop such as lupins in the beds where you intend to plant them. Lupins fix nitrogen to the soil which is important for these two summer mainstays because nitrogen-depleted soils promote bolting or early seeding.

* Once the seedlings have germinated, cover with shade cloth for a couple of weeks to encourage the young seedlings out of the ground a bit. Don't let them grow through the webbing though or you'll rip the young plants out of the ground when you remove the cloth.

* Direct sow root crops into well-tilled soil. For all you no-dig gardeners out there, apply some seed-raising mix to the surface of your bed to help germinate the seed. I add a small amount of sand which keeps the beds a little warmer and also improves drainage. Make sure the beds are kept well watered as improved drainage means less water in the soil.

* Move rogue germinators around the garden. Start by cutting the soil around emerging plants using a garden trowel, leaving a root ball of around three inches. Leave the young plants in the ground for a month or so to let them develop then transplant them into their new home.

* Spray roses prophylactically with baking soda and garlic spray. The baking soda will help the plant fight black spot infections and the garlic spray will deter sucking insects which spread disease.

General garden care
* Cover all landscape areas with a thick layer of mulch over cardboard making sure it is overlapping. This will suppress weeds and help keep the soil moist over summer.

* Trim hedges to encourage bifurcation. Its important not to leave it too much later (I'm talking to myself here) because once summer hits and things dry out, the rate of growth will reduce, negating the benefits of trimming.

* Make sure you enjoy the warm weather safely and slip, slop, slap.

* To ask Justin a question, click on the Email Justin link below.