Justin Newcombe: Space savers

Landscape gardener and Life columnist Justin answers your questions.

We don't have a great deal of room in which to start a proper garden, and our section is built on clay. Is it possible to have a raised garden (like one of the kit-set gardens) placed at the end of our concrete driveway? I'd have to seal the base, of course, but I'm wondering if there would be enough depth for a wide variety of crops. We'd like to work it as a square foot garden - and perhaps use the old Native American trick of having squash and beans growing in the same mound as corn. Any ideas or suggestions? Money's always an issue, but hard work is no problem at all.

- The Butlers

With not much room available intensive gardening using the square foot method make good sense. The planting of squash, beans and corn together is known as the three sisters. I usually do the corn and squash but not the beans. In your situation I think this method would use up too much space. I'd probably not bother with corn and grow the squash up a frame with only the root on the ground. Last year I grew a pumpkin up a fence and the pumpkins stayed on the vine until it died in autumn. You can use the square foot method in combination with no dig or sheet mulch gardening. Because your soil will be encased on concrete the no dig/sheet mulch method will help revitalise your garden. On concrete I would recommend a container at least 400mm high, with irrigation. You could use sleepers as the edging. They look great and give you something to sit on plus you can always go up a layer at a later date if you find you'd like a deeper garden.

Thanks for the interesting info on sandwich gardening. My garden is a narrow strip next to the apartment, running down at an angle that becomes quite steep. The garden gets lots of sun (more in winter) and is little affected by frost. It currently has terrible soil but any "bought in" soil has to be carried up steps, so the less the better! Is an angled garden suitable for sandwich gardening? Would it be wise to terrace the lower portion first?

- Andrea

Yes, I think sandwich gardening would work well in your situation. The addition of soil can be hard work I agree but formula one soils, like those found in Pukekohe, would be well worth the labour of bringing in. Other options are to use bags of compost which are relatively light to carry and to colonise the garden over time. To keep the soil from eroding try using ponga logs cut into sections to form steps, a bit like rice paddies.

WHAT TO DO RIGHT NOW

Vege garden
* Sow all your nightshades - that's tomatoes, peppers and aubergines - in trays. Also sow sweet corn and sunflowers. These can be direct sown if you reckon the weather is warm enough. Or you can plant the seed in deep trays and get them going in a hot house or cold frame, ready to plant the young plants out in two to four weeks.

* Also plant cucurbits, squash and melons in trays but make sure you put them inside overnight. When they are ready to plant out, try planting vines such as pumpkin, courgette or cucumber on the ground underneath the corn or sunflowers. The cucurbit vines shade the roots of the taller plants and allow you to get double the crop out of a single space.

* If you are sure Jack Frost won't be making a late visit, plant your spuds. Use good seed potatoes from your garden centre. Don't forget to chit or sprout your potatoes before you plant them. Do this by placing them in a warm sunny spot and they'll do the rest. Make sure your potatoes are not planted in the same position that they have been in any of the previous three years. To keep black spot at bay, dress the farrows with milk powder every couple of weeks as a top dressing will also help. If things get really bad mix up the milk powder with water and spray the infected plants.

* Put kumara tubers in a box of sand and keep in a warm spot. Once the tubers have grown to about 20cm, break them off and plant them. I grow the vines up stakes which keeps them off the ground, ensuring I get nice big tubers.

* Direct sow snow peas, spring onions, turnips, parsnips, radish, beets, broad beans and carrots.

* Feed garlic with a dressing of blood and bone and weed leeks and onions.

Flowers
* Sow sunflowers, marigolds and calendula, petunias, carnations, cosmos, cornflowers and hollyhocks for summer.

* Move rogue poppies and other annual seedlings around the garden to somewhere you can enjoy them.

* Plant lavender and feed roses. Spray roses prophylacticly for aphids with Tui Eco Pest. Aphids thrive on the young shoots.

In general
* Use mulch to retain all that moisture we've been given this spring. It keeps the weeds under control.

* Get ready to sow everything. Now is the time to set things up for your garden. But don't worry if your seeds don't come up as planned. That's what punnets at the garden centre are for.

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