Vegetable Garden FertilisersFertilising and Mulching your vegetable garden has many benefits, read on to see why, or, use the following links to jump down to specific topics.
How to Fertilise a Vegetable GardenVegetable fertilising should be approached for two different purposes, each working towards the same goal. Healthy, vigorous and productive plants. This is either fertilising in preparation for planting, or, fertilising maturing plants to improve growth and health. Depending on the plants, different approaches are needed.Basically, we need to fertilise the vegetable beds in preparation for planting. This is done in advance of planting and then we need (in some circumstances) to fertilise plants when they are growing/producing.
This page will deal with different types of fertilisers suitable for vegetable gardens and fertilising beds in preparation.
Fertilising specific crops is dealt with on the plants page under each type as well as in crop rotation.
I'm not going to lecture you on the pro's of organic vegetable gardening and natural fertilisers versus the perceived "evils" of chemical fertilisers. What you choose to use is entirely up to you. What do I prefer? Well I mostly stick to natural sources. Why? well in my opinion, if used properly, they are just as effective and generally cheaper. SO... Let's look at why we fertilise first, then what job each does. Plants use minerals in the soil, often referred to as trace elements, water and nitrogen, phosporus and potassium to grow. Most chemical fertiliser packets display the ratio of the contents of these by their chemical symbols (NPK) and show them as the NPK ratio. Don't worry, there's no chemical/science lesson coming here. The basics you need to know are that Nitrogen encourages green leafy growth and potassium, also called potash, promotes flowering. So anything you want to grow, where the main part you eat is the leaf, like say a lettuce or silverbeet, spinach etc loves nitrogen and anything that needs a flower to produce the part you eat, such as tomatoes and other fruits, also need nitrogen, but a reasonable dose of potassium, to encourage the flowers to make the fruit.
Natural sources of vegetable garden fertilisers basically come from the following:
Now these sources naturally have differing levels of strength and get used for different reasons. Chicken manure is typically high in Nitrogen and can be quite strong so it has to be used with care. Cow and Horse manure are weaker and are generally used as soil conditioners and aren't usually a great food source for plants. Care has to be used if you source Horse manure from a stable as it is usually saturated in urine and can burn plants. It should be left in a pile to compost down for a few weeks. Sheep Manure, often affectionately referred to as "garden marbles" because of their shape is somewhere in the middle. Blood and bone mixes are sold commercially as a powder and can vary in "nutritional value" so check the labels and compare brands. How much to use depends on the size of your bed, what you're planting and when. Let's look at my vegetable garden beds as an example. Each is around 10ft x 5 ft.(2.4mtr x 1.5mtr) If I was preparing a bed for spring/summer planting of leaf crops, like lettuce, cabbage, broccoli, cauliflower etc. I would use the following: 1 sack of sheep manure
Around 1-2 kg's pelletised chicken manure
About 500g to 1kg of blood and bone.
spread evenly over the top of the bed, lightly raked in, watered and then heavily mulched.
Fertiliser "Teas"
This term basically refers to making your own liquid fertilisers from manures/worm farms. Basically using one of those porous animal feed sacks (or the one's the sheep manure usually come in) place a couple of kilos of your chosen manure in the bag and immerse it in a large bucket of water for a few days. (Not too long. 
This will leach the nutrients into the water and looks like strong tea. Using the resulting "tea", watered down in a watering can to liquid fertilise established crops, such as winter growing plants like cauliflower, cabbage and broccoli which are hungry feeders. The liquid fertiliser is more rapidly taken up by the plants, giving them that extra boost as they near harvesting. 
When the fertiliser tea is ready, in our case after a week, lift the bad of pellets out of the bucket and let the liquid all drain out. Although a lot of nutrient will have leached out, the remaining manure pellets, which most likely have turned to a mud like consistency, can still be used on your garden beds, so don't throw it out. The "brew" that we achieved came from about 1-2 kg's of pellets in 10 ltrs of water. This brew needs to be watered down as it is far too strong to apply directly. Although you'll have to experiment, we found that 500ml of this concentrate in a 10 litre watering can was about right. (be guided by the colour of the diluted mix) Water all of the plants that need a feed with this diluted mix as a foliar feed (water over the leaves as it is absorbed directly)! Your brassica plants will love it and will get a real boost Seaweed ConcentrateSeaweed concentrates are not strictly a fertiliser, and might be better referred to as a "tonic". There are quite a few brands around, but the science that applies is the same. Basically, the chemical makeup of the solution that is produced from seaweed, stimulates the strengthening of plant cell walls and also cell division.We always use a mix of a seaweed concentrate when planting seedlings and/or transplanting plants. This is because the mix is excellent at minimising transplant shock that occurs when plant roots are disturbed. Some plants are more susceptible to this than others.
We have trialled seaweed concentrate on a range of plants with great results.
Australian native plants can be very temperamental when planted out. We planted two beds, one treated and one not. We had a 100% success rate with the treated bed and only about 60-70% survival with the other.
Having also endured a 10 year drought, we have also found that it greatly helps plants under these stressful conditions. A recent trial found that another well know crop brand, that comprises naturally sourced fertilisers as well as seaweed "extracts" does the trick of not only boosting the plants but also gives them a a liquid fertiliser feed as well.
Green Manure
A Green Manure bed basically is a bed that is sown with a mix of seed that is allowed to germinate and grow to a low, lush green growth, then is chopped up and dug back into the soil and mulched. Over the following weeks, all that luscious green plant growth composts down in your bed, adding vital nutrients and organic matter 
If you can leave your bed to grow a green manure before spring, before you go and dig all that compost in, add some sheep manure and a light dressing of chicken manure.
With the compost and manures dug in and the soil surface evenly raked, spread your green manure mix evenly over the surface then lightly rake the surface again. This will help the seed get in contact with the soil better, then give the bed a good water.
Two weeks after sowing
When the green manure is around 40cm high, some plants may be just about to flower, it's time to dig it in. With a sharp spade, chop the growth up and dig it into the soil. 
When you're all done, mulch the bed with your choice of mulch and, depending on when you do this, leave it until Spring, or few 3 to 4 weeks before planting. (Make sure you check how the composting is going before planting). The image that follows is the same bed mulched with Sugar Cane mulch. Mulching a Vegetable Garden
How do you mulch a vegetable garden and why? Mulching is a process where a range of different materials is used to cover the soil in a garden.
When it comes to vegetable gardens, some care needs to be taken in the choice of materials used.
Mulching provides a numbe of benefits in the vegetable garden. One thing to remember though, not all vegetable plants like mulch up around them, and in these instances, you have no choice but to gently hand weed to keep on top of them.
Types of Vegetable Garden MulchThere are a lot of different mulches that can be used on a vegetable garden. These are the one's that I have the best over the years.
Pea Straw Pea Straw is a waste product from commercial pea crops (but is also grown for mulch and feed). Once the peas are harvested, the dead pea plants are gathered and compressed into bales of "straw". Crops of peas are also grown solely for the purpose of producing pea straw. The straw is densely packed and comes apart from the bale in "biscuits" that you need to pull apart and spread around. This is easier if done before planting. Lucerne Hay Lucerne is a crop that is grown primarily as a feed crop on farms. Once matured, like other hay crops, it is allowed to dry, then is cut and baled. Like Pea Straw, Lucerne is densely packed and will separate in biscuits from the bale. 
Sugar CaneIf you are lucky enough to live in a country that produces sugar cane crops (like I do), you should be able to find Sugar Cane mulch quite readily. This is a waste product of growing sugar cane. After harvesting, the remaining material is dried and chopped to produce a light and easily spread mulch layer. Return to Vegetable Garden Homepage |
