Plant Feeding


 

Overview:

It is often assumed that poor growth in garden plants is related to lack of fertiliser.

This is not always the case as some other factor/s may be causing the non-uptake of nutrients from the soil.

Things such as an imbalance in nutrients, wrong soil ph, soil too dry/too wet or disease to name but a few.

A soil test is the best way to establish such problems.


As a rule of thumb:

Plants in containers will need regular feeding.

Plants in the borders will generally survive for the season on a top dressing of a general or balanced fertiliser at planting out time.

Perennials usually require feeding when new growth commences.

Fruit bearing and flowering plants will often benefit from a high potash feed when the embryo fruit or flower buds appear.

*See the list below for feeding times of specific plants.


Plant feeding:


The nutrients a plant requires for growth are, nitrogen, phosphorus and potash (NPK), supported by a range of trace nutrients.

The first three nutrients are required in large amounts but the ratio can vary a lot from crop to crop.

For example; brassicas such as cabbage require higher amounts of nitrogen than root crops such as onions or carrots, where as shrubs and trees need more phosphorus and potash.

The same is also true of the trace elements, as the term implies, only a trace is required, for healthy growth even if there is enough NPK available.

Nitrogen (N) is necessary for development of leaves and stems.

Phosphorus (P) is for strong root systems.

Potash (K) is for healthy fruit, tubers, and leaves.

Where possible, choose a formula that matches your plant's requirements.


Soil characteristics:


Soil conditions can influence the availability of nutrients, e.g. soil compaction and water-logging can stop essential nutrients being usable.

Light, sandy soils are often high in phosphates and low in potash.

Clay contains lots of potash that becomes available as the soil is aerated and limed.

Accurate assessment can be made by soil analysis, to determine deficiencies.


Application times:


Bulky, animal manures, mushroom compost and garden compost are best applied during the dormant season.

They can either be applied as surface mulch, or dug into the soil.


Adding lime to the soil is an important resource, but is determined by the amount already in the soil and the type of plants being cultivated.

Check your soil pH and add lime as necessary.

Sandy soils usually lack lime.

Avoid over-liming as this could lock up some trace elements.

Do not add lime to recently manured soil!


Feeding times:


Genus


Feeding Time



Genus


Feeding Time

 

Asparagus


Before growth stars in Spring

 

Aubergine


After fruit sets.

Broad beans


After pod set.

 

Broccoli


Three weeks after planting out, then as required.

Brussels Sprouts


Two to four weeks after planting out or when plants are 300mm high.

 

Cabbage


Three weeks after planting out.

Calabrese


Three weeks after planting out, then as required

 

Cauliflower


Three weeks after planting out.

Cucumber


One week after plant blossoms and again three weeks later.

 

Globe Artichoke


Planting time and monthly top dressings.

Gourds / Squashes


A month after emergence from soil.

 

French beans


After pod set.

Kale


When plants are approx 300mm (12") tall.

 

Lettuce


Two/Three weeks after transplanting or emergence from soil.

Melons


At planting out time.

 

Onions


When bulbs begin to swell.

Peas


Once established and when pods set.

 

Peppers


After fruit sets.

Potatoes


When in flower.

 

Rhubarb


Before planting out.

Runner beans


After pod set.

 

Spinach


When plants are approx 300mm (12") tall.

Sweet corn


When 200mm (8") long and again when silks appear.

 

Tomatoes


After fruit set then weekly.

Water melon


When plants are approx 300mm (12") tall.  

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