Saturday, December 6, 2008

Gardening at the Beach

It was great to see such an awesome turnout on Saturday, when thirty people turned up to North Beach to hear Charlotte talk about her coastal garden.

Establishing the Vegetable Beds
When Charlotte and Scott first moved into their place eighteen months ago, the property already had a lot of established native trees and shrubs. However, to get their vegetable garden started a little more effort was required.
Knowing just how hungry sandy soil can be, they decided to kick start their garden with a few cubic metres of top soil. A layer of topsoil (10-15cm deep) was laid onto the grass and edged with bricks from the old chimney. Before planting they lightly forked a layer of composted chicken manure into the new beds. ‘It is always a good idea to dig in some compost first, as topsoil often contains silt and clay, which can bake hard and crack in the sun’, says Charlotte. Compost is a wonderful substance that improves all types of soil; while compost helps light, sandy soils retain moisture and nutrients, it also improves aeration and drainage of heavy soils.

Green Manure and Seaweed
The best vegetable bed — seen above — was enriched with seaweed and green manure over the winter. Seaweed was laid in shallow trenches and covered with soil. Oats, lupins and broad beans were sown over the top in April, and the green manure was dug-in during August. The soil in the green manured area is noticeably better than the soil in other beds. The organic matter has broken down to create sticky humus, which binds the sand particles together, enabling the soil to hold water and nutrients.

Nothing Wasted
Scott and Charlotte don’t like to take any organic matter off their property. A huge pile of tree prunings sits in the middle of the garden as testament to this philosophy. ‘One day we will get a mulcher’ says Charlotte, ‘in the meantime the pile is home to many invertebrate species, and is fondly known as the “spider cave”’. Weeds, grass clippings and old vegetable plants are mixed with straw and composted; all the household’s kitchen waste is recycled using bokashi buckets. Occasionally the pair source enough manure and straw to make a large compost heap, but most of the time they just use rotted down seaweed, or buy in composted chicken manure. ‘If you are using manure make sure it isn’t contaminated with herbicides. Sometimes farmers spray herbicides on their fields to kill broadleaf weeds and these contaminants can get into the manure’ says Charlotte.

Hardy Coastal Plants
Although most of Saturday’s talk was devoted to the hows and whys of vegetable gardening, Charlotte found some time near the end to recommend some hardy coastal plants. ‘It is a good idea to plant wind and salt tolerant trees on your NE boundary ’, says Charlotte, ‘once you have established your first line of defence it is possible to plant more tender plants on the leeward side’. The plants Charlotte recommends for coastal gardens are listed below:

Ngaio Myporum laetum
Coprosma lucida, C. robusta, C. repens
Pittosporum tenuifolium, P. eugenioides, P. crassifolium
Broadleaf Griselinia littoralis
Kowhai Sophora microphylla, S. prostrata
Olearia paniculata, O. ilicifolia, O. avicenafolia, O. traversii
Akeake Dodonea viscosa
Kanuka Kunzea ericoides
Cabbage tree Cordyline australis
Corokia x virgata, C. cotoneaster
Coast banksia Banksia integrifolia*
Olive Olea europaea*

NZ lilac Heliohebe hulkeana
Hebe species (especially H. odora, H. salicifolia, H lewissii, H. speciosa, H ballensii)
Marlborough rock daisy Pachystegia insignis
Kaka beak Clianthus puniceus
Brachyglottis greyii
Muehlenbekia astonii
Coprosma propinqua C. virescens

Rock rose Cistus sp*
Coast rosemary Westringia rosmarinifolius*
Rosemary Rosmarinus officinalis*
Lavender Lavandula sp*
Wax flower Eriostemon myoporoides*
Grevillea sp (choose frost tolerant species)

Rengarenga lily Arthropodium cirratum
NZ Iris Libertia peregrinans
Dianella sp.
Gazania hybrids*
African daisy Arctotis hybrids*

Ground cover
Native daphne Pimelea prostrata
Pratia angulata
Fuchsia procumbens

Shield fern Polystichum vestitum, P. richardii
Hen-and-chickens fern Asplenium bulbiferum
Hound’s tongue fern Phymatasorus diversifolius

All plants are native to New Zealand, except those marked by an asterix* .

Posted by Charlotte McHaffie