Plant food know-how: How and When to Feed Your Plants

Are you confused about feeding your plants? Geoff Hodge explains what you need to know.

Richard feeding plants using hose end sprayer

How would you feel if you spent a year without getting regular platefuls of your favourite meals? You’d be run down, stressed, unable to perform properly and become very ill, very quickly. Well, it’s the same for your plants. They need a regular diet of the right plant food to grow well, flower and fruit. Yes, they can get some nutrients from un-fed soil, but they do so much better when they’re fed. Correct feeding also produces strong, healthy plants that perform brilliantly, as well as helping them to fend off pests, diseases and environmental problems – such as extremes of cold and heat. Knowing how and when to feed your plants can make the world of difference to your garden.

Feed me – feed me now!

Plants in containers are especially in need of a good square meal on a regular basis. Unlike plants in the ground, they can’t send their roots off in search of new food larders. Most good potting and multi-purpose composts have enough food to feed for around five to six weeks, sometimes a lot more. But after this time, you’ll need to be the plants’ hunter, gatherer and provide them with some plant food. But which fertiliser or plant feed – they mean the same thing – should you use? Here’s our guide to what to look for.

Plant food & nutrients

The main nutrients plants need are nitrogen (N), phosphorous (P) and potassium or potash (K), represented as the NPK ratio on the container. Although they do other things for the plant, generally nitrogen encourages good green leaf growth, phosphorous strong root growth and potash promotes flowering and fruiting. Potash also promotes harder, stronger, more disease-resistant growth. They’re like our main, three-course meals. We’ve covered the importance of NPK in another feature. Other nutrients are also needed, but in smaller amounts (such as magnesium and iron), and some in tiny, but crucial amounts, called micronutrients or trace elements. These are like the vitamins we consume, which humans need to ensure we stay strong and healthy.

Richard feeding plant with Flower Power
Image: Richard Jackson Garden

Fertiliser types

Plant feeds come in a range of formats, which can be divided into three types, depending on how they are applied and how long they feed for. Liquid feeds, sold either as granules or a powder that is first dissolved in water or a liquid that is diluted in water, as their names suggest are applied as a liquid – either in a watering can or by hose-end feeder. They have the advantage that because they’re a liquid, they get to work immediately, are very fast acting but, as a result, the nutrients are used up quite quickly. So they have to be applied regularly – usually every couple of weeks while the plants are growing. They’re also perfect for giving plants a quick boost, tonic or a ‘pick-me-up’. Richard’s Flower Power is a great example, sold either as a powder that you dissolve yourself, or as an organic liquid plant food.

The other advantage of some – but not all – liquid feeds is that they can be absorbed by the leaves when applied as a foliar feed; that is they’re applied over the foliage. This is particularly useful when you need to quickly supplement nutrients in the soil and where leaf or flower problems are caused by inadequate soil nutrients. Richard’s Flower Power does work as a foliar feed.

Solid or granular feeds are applied dry and are usually sprinkled around the plant on the soil or compost, and are often called slow-release feeds. They only start to work when they break down in the soil and the nutrients dissolve, so they are slower to start working, but they will feed for a few weeks, sometimes up to several weeks. Organic feeds, such as blood, fish and bone, are also called slow release, because the complex plant nutrients they contain have to be broken down by soil bacteria and fungi into simpler, soluble forms that plants can absorb. They can feed plants for several weeks, but can take up to three months before the nutrients become available to plants.

Controlled-release fertilisers are ‘clever’ feeds. They slowly release their nutrients in a controlled way, only when the conditions are right for plant growth and when the plants need them, so you can’t overfeed or underfeed and there is minimal wastage. They can feed plants for up to six months, so one application in spring is usually all the plants need for the whole growing year. As well as feeding for a long time, they’re perfect for busy people or those who forget to feed their plants regularly. Richard’s Easy Feed is a great example of this type of fertiliser.

How and When to Feed Your Plants. What else to consider?

There are a few other soil factors to consider if you want to grow great plants. Keep it moist – Because plants don’t ‘eat’ their food – they absorb nutrients in solution through their roots – the soil or compost must be moist. If the soil is too dry, it will prevent the nutrients from being taken up. So, it’s important to apply to moist soil or compost – and another reason why liquid fertilisers are so useful. Keep breathing – Roots need air to live, so lots of small, fine channels in the soil are essential. Your plants won’t appreciate compact soil, such as heavy clay soil, with little or no air spaces.

Organic matter to the rescue

Fortunately, organic matter, such as garden compost, well-rotted manure, leafmould or composted bark, can help improve all poor soils. Mixed into the soil, it improves the structure, increasing its water- and air-holding capacity.

Feed the soil and your plants with Flower Power Natural Fertiliser. Image: Richard Jackson Garden

But it also has other amazing properties in helping to promote healthy plants. The increased humus in the soil increases microbial activity and it is the food source for essential friendly soil flora and fauna including micro-organisms, soil fungi and bacteria needed for a healthy soil. This is the main principle of organic gardening – a healthy soil means healthy plants. Richard Jackson Natural Fertiliser has been developed to feed your garden plants and gently improve your soil at the same time. A special combination of natural poultry manure, trace elements, extra potash and magnesium, this granular fertiliser is a must-have for your borders and allotments, or even used when planting.  It is also the food source of the much hyped, almost mythical, mycorrhizal fungi. These are naturally occurring fungi that attach themselves to the roots enabling the plants to absorb more nutrients and water, so they grow better, as well as making them more drought tolerant.

Acid or alkaline?

Soil pH (its acidity or alkalinity) is also important. Some nutrients become “locked up” in the soil at pH extremes, which is why the leaves of rhododendrons, camellias and other lime-hating, ericaceous plants turn yellow in alkaline soil – they can’t absorb enough iron from the soil, which is locked up at the high pH.

Special help

If you want to give your plants a very special boost to the start of their life, add products like Richard’s Root Booster. The special formulation does three amazing things: it locks in nutrients when you feed your plants, so they don’t leach out as easily; builds a stronger root system, so plants grow better; develops a healthier, more disease- and weather-resistant plant.

Richard using Root Booster
Adding Root Booster when planting helps to build a stronger root system. Image: Richard Jackson Garden

It does this thanks to its three special ingredients: humates (found in humus) boost root growth and help fertilisers work more effectively; seaweed extract is a natural bio-stimulant that also conserves moisture in the soil/compost, so you shouldn’t have to water quite so often; special plant food that gently boosts plant growth in the first few weeks. Humates and Seaweed Extract can also be found in Flower Power Plant Food. So, if you want the best quality plants around, then feed them – feed them now!


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