Adding compost or a soil improver helps to provide the right growing conditions, which will ensure you achieve bigger and healthier results. Find out how to choose the right compost for you.
What you need to know about compost is...
Some garden soils can be good for growing plants/fruits/vegetables, however they can vary considerably (even within the same garden) and very few gardeners are lucky enough to have perfect soil. Adding compost or a soil improver helps to provide the right growing conditions, which will ensure you achieve bigger and healthier results.
Choosing the right compost is essential to get the most out of your plants/fruit/vegetables, but the ingredients that make up different composts can vary dramatically. For the best results it is wise to use a fit for purpose compost, which has been tailor-made for the job in hand.
Broadly speaking, there are five different types of compost:
There are many formulations of peat based composts available to the gardener. These are made from a base of peat blended with other ingredients such as fertiliser, sand and/or grit, vermiculite or perlite, wetting agents and lime. The exact formulation will depend on the intended use of the compost.
John Innes Composts are soil-based growing media made from a mixture of loam, sand or grit and peat with increasing amounts of plant foods added. John Innes Seed Compost contains the smallest amount of nutrients as this encourages the best germination and growth of tiny roots and shoots. John Innes No.1 Compost contains slightly more nutrients and is for transplanting seedlings. John Innes No.2 Compost for when you are potting up small plants and John Innes No.3 Compost has the most nutrients, as this is designed for final planting up of plants ready for display or cropping.
Peat free compost can be made from several different base ingredients, such as wood fibre, composted bark, coir, and green compost.
Specialist composts are then produced using one of the above as a base, to which other ingredients are added depending on what they are to be used for. These come under the following headings, which also has an explanation of what they consist of and where they are used.
Organic composts contain a mixture of materials e.g. peat, expanded wood fibres and composted bark in varying proportions. They are enriched with naturally occurring nutrients, derived from plants and animals, to feed plants for differing periods depending on the organic compost purchased, some feed for up to 3 months. In addition, composts may be certified as organic by organisations such as the Organic Farmers and Growers Association.
This is a compost that can be used in various parts of your garden, from beds and borders, to pots, containers and hanging baskets. They come in different blends of ingredients, for example, some contain varying plant foods that will feed your plants anywhere from 6 weeks, up to 6 months – others will limit the amount of watering you need to do, by absorbing water then storing and releasing it as and when the plant requires. You can get peat free and added John Innes.
* Versus ordinary garden soil
Bark can provide a clean visual background that makes plants and flowers stand out. However, applying a layer of organic material, such as bark (known as mulching), does more than make your garden look attractive, it also helps to retain soil moisture, suppress weed growth and will gradually improve the structure of your soil.
You can get other various types of mulch, such as pebbles, sea shells, slate, cocoa shells and coloured wood chips.
This compost has a more open texture which helps with root growth and has little nutrient content, as bulbs themselves don't really need them to develop until flowering stage. This compost normally has ingredients such as charcoal or oyster shells in it, which keeps the compost fresh.
These are great if you are limited on growing areas in your garden, as they take up very little space and can be placed just about anywhere. You can grow all sorts of wonderful fruit, veg and herbs, from salad leaves, Tomatoes, Carrots, Potatoes, Onions, Strawberries and Cranberries. Most will have a plant food mixed in, that will feed for up to 8 weeks, after this time you would then need to feed regularly, you can also get peat free and special water absorption ingredients mixed in.
Perfect for all fruit and vegetable gardening, this compost is guaranteed to grow twice the amount of fruit and vegetables as an ordinary garden soil. It’s specially formulated with organic plant food and feeds for up to 6 weeks.
John Innes Composts are soil-based made from a mixture of loam, sand or grit and peat with increasing amounts of plant foods added. Levington John Innes Seed Compost contains the smallest amount of nutrients as this encourages the best germination and growth of tiny roots and shoots. Levington John Innes No.1 Compost contains slightly more nutrients and is for transplanting seedlings. Levington John Innes No.2 Compost for when you are potting up small plants and Levington John Innes No.3 Compost has the most nutrients, as this is designed for final planting up of plants ready for display or cropping.
This compost is best for starting plants off, either seedlings that you have grown and are at the next stage or young plants you have brought. Most will have the added extras that your young plants need, to help them develop into strong healthy mature plants.
The best start for your plants
* Versus ordinary garden soil.
Young seedlings are very sensitive to their environment and need different nutrients and care to more mature plants. Normal potting composts are too rich in most of the nutrients, and have a texture that is too coarse for fine seedling roots to penetrate. Specialist seedling compost have generally lower nutrient levels but higher phosphate, which helps to develop a strong root structure. It also has a finer texture to create the perfect surroundings for the young plants to flourish.
With a specially balanced nutrient mix ideally matched to the needs of developing seedlings, young plants, and newly rooted cuttings, this compost features a traditional mix of loam, peat and grit.
These are used to improve aeration and drainage in heavy clay soils and adds body to light sandy soil, which aids in retaining moisture and nutrients. It also boosts the soils fertility by adding some nutrients, that will encourage healthy foliage, flowers and root growth.
Covers a multitude of specialist plants from Roses, Ericaceous, Cactus and Bonsai's, all of which have specific requirements from the soil they are grown in. Each dedicated compost will contain what that specific plant needs, and if you try and grow these in the wrong soil environment, then they can produce poor growth.
Q: Can I re-use my patio pots year after year?
A: You can certainly re-use them, but it’s best to tip out all of the old compost and then wash the containers thoroughly with warm soapy water, followed by a good rinse with a solution of cold water and a garden detergent. It’s important to do this because your existing compost may be harboring vine weevil larvae and other garden nasties. It’s far better therefore to have a spring clean and thus minimise the risk of pests and diseases infesting or infecting your new displays.
Q: Why can’t I use my own garden soil to pot up plants?
A: Garden soil doesn’t hold as much water as a good potting compost and so you will have to water more often or your plants will suffer. Soil also lacks essential nutrients and so plant growth will be slower. Garden soil may also harbour pests and diseases.
Q: I've opened up my compost and it looks like an insect has laid eggs in it
A: This is most likely to be the small round coloured granules, which are the controlled release fertiliser, that when squeezed will pop open releasing a liquid which is the fertiliser concentrate. The fertiliser cases have a semi permeable membrane, which allows water inside to dissolve the nutrients within them. The nutrients are then released back into the compost in a soluble form for the plants to absorb. The cases will naturally breakdown in the compost over time.
Q: How can I find out whether my soil is suitable for rhododendrons?
A: The best way is to use a pH soil testing kit. If the results show your soil is naturally acidic then rhododendrons, azaleas, camellia and the like will thrive. If it’s neutral then you can still plant away, but feed with a special plant food that’s been formulated for acid-loving plants such as Miracle-Gro Water Soluble Ericaceous Plant Food. If you’ve got alkaline soil then your best bet is to plant the rhododendrons in a container filled with a suitable ericaceous compost – try Miracle-Gro Azalea, Camellia & Rhododendron Enriched Compost - and then feed with an ericaceous plant food throughout the Summer.
Q: Can you explain the differences between the John Innes composts?
A: John Innes Composts are soil-based growing media made from a mixture of loam, sand or grit and peat with increasing amounts of plant foods added. Levington John Innes Seed Compost contains the smallest amount of nutrients as this encourages the best germination and growth of tiny roots and shoots. Levington John Innes No.1 Compost has slightly more nutrients and is for transplanting seedlings. Levington John Innes No.2 Compost for when you are potting up small plants and Levington John Innes No.3 Compost has the most nutrients, as this is designed for final planting up of plants ready for display or cropping.
Q: This compost looks different to previous years
A: Most compost producers are following Government & Industry guidelines to reduce the peat content of their composts. At Miracle-Gro, we are justly proud of our environmental record and our wide range of composts contain varying levels of peat from Levington Seed & Cutting Compost which contains peat to New Miracle-Gro Expand ‘n Gro™ Enriched Compost which is totally peat-free. The rest of our products have varying levels of peat and peat substitutes, so that we are able to reduce the total amount of peat used by gardeners.
You will find peat bars displayed on the back of packs like the example shown above. One of the number sections will have a tick inside it, to indicate how much peat the product contains.