Applying mulch
Generally all organic mulches are applied in layers of around half a finger deep - with straw and seaweed this may be more like a full finger length. Carpet, weed-proof membrane and black polythene are all much thinner than this.
Avoid contact between mulching material and the stems of plants where possible as this can cause them to rot. Organic mulches often need to be reapplied as months pass and they decompose. (Weed seeds will often germinate in the upper layers of old mulch and re-applying helps to prevent this)
Types of mulch
Mulch comes in a variety of forms most of them are organic and are also beneficial to soil adding nutrients and improving structure as they bio-degrade.
Organic mulches
Compost, manure and seaweed
These all look after the soil whilst also providing beneficial nutrients as they break down. They can be heavy if large quantities are required. Sheep pellets are also used as a mulch but this can get a bit pricey in large areas.
Seaweek coils around artichokes
Pea straw and straw
These can be used over wide areas as they spread well and retain moisture. Use straw rather than hay that can have a lot of seeds in it.
Pea straw is better for small seedlings as it is finer and spreads evenly; straw is good for strawberry plants, zucchini, melons, pumpkins etc. Both are fairly lightweight and go a long way, wet as soon as you have applied them to keep them from being blown around.
Leaf mould
Dry leaves from deciduous trees that lose their leaves in autumn can be used a mulching layer but they tend not to stay in one place for too long. Better to add to compost and then mulch with the resulting rotted material.
Pine needles
Particularly good for mulching around strawberries and blueberries - that favour a slightly acidic soil.
Strawberry plants surrounded by young pine needles
Lawn clippings
Use sparingly, best if layered thinly with other mulching materials such as shredded paper, compost and pea straw.
Untreated wood shavings, shredded bark, wood chips
These all take some time to bio-degrade and so are a long-life mulch. Better used around shrubs and trees rather than fast growing vegetable plants.
Cardboard, newspaper
Useful alternative to other organic mulches. Shred newspaper and wet as soon as you lay it - this should stop it from blowing away.
Old carpet
Use a wool-based carpet and avoid fitted carpets with adhesive.
Inorganic mulches
Black polythene
Also suppresses weeds but does not facilitate good airflow. Polythene really heats the soil beneath it during daytime and this can kill many micro-organisms and invertebrates - so not so cool. It is fairly easy to use - you can leave it down and cut holes in it when planting. May not be recyclable.
Weed-proof membrane
A purpose made black fabric that allows water and air through but deprives weeds of light. You can use this under strawberry and melon plants.
Gardeners on the go
Feed gross feeding plants like zucchini, tomato, capsicum and egg plant every two weeks with liquid feed and step this up to weekly feeds once fruit start to form.
Pull weeds daily from between crops like carrots, lettuces, beetroot and peas.
Repeat sow salad crops, herbs like coriander, peas, dwarf beans to prolong harvest
For full-scale, seasonal edible gardening advice and inspiration see www.podgardening.co.nz or check out Pod Gardening on facebook.
