What is HIGH POTASH plant food?

I say on my BBC Radio Sheffield's garden phone-in "you need to use a high potash feed


This can be confusing if you don’t know what it means and worse if you try and buy them from an outlet without their own garden expert.

All plant foods (fertilisers) have printed on their packs the proportion of N, P, & K that are in the packs. N stands for Nitrogen, P stands for Phosphorus (phosphates) and K stands for Potassium (or potash). 7:7:7, this being a balance fertiliser, 10:5:3: a plant growth feed & 5:5:12 is a high potash feed or Potash Fertiliser. These figures will vary but look out for their relative proportions.  Next time you are in the garden centre have a look at the different feeds and see how they vary depending upon the type use.


flowerJust a note on Tomato Feed: They are very high in Potash (K) and initiate flowers and then tomatoes but tomato feed is also high in nitrogen (N) for growth. The high N is to balance the very high K (potash) which is very import for tomatoes, this means it can be too ‘strong’ for other plants. If you would like to use  it for other plants dilute it by 50%.

Nitrogen encourages green growth, Phosphates (phosphorous in soluble form) is essential for healthy growth and good for roots, Potash (potassium in soluble form) not only produces more flowers and good fruit but also, makes plants tougher and resistant to diseases and pests.

Last of all, if you feed too much with high N or balanced feeds you may stop flowers forming (why would they need to flower? They are happily growing away). If this is the case stop using these feeds, water with plain water for a week or two & then feed with the high potash food.

Still not sure? Call us on air on BBC Radio Sheffield between 9 & 10 am every Sunday on 0114 279 6699.

Keep both of the following as essential ‘tools’ for successful gardens  and plants.

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    1. Hello Albert, The usual cause of greenback is excessive heat in the greenhouse during the development of the fruit. Not surprising this year.
      The risk of this can be reduced by applying white shading to the glass in early summer, damping down the greenhouse paths in the morning on hot summer days, and ensuring that there is adequate ventilation. Removing some side or end panels might help get better air circulation. All of these measures will help to reduce plant stress on hot days. Whilst it may be too late this season, we would recommend using all 3 of these measures next time and possibly now to help the later fruit.

      Greenback can also linked to a lack of potassium. Feed the plants regularly with a high potash feed regularly to prevent this disorder. we like this one :

      hope this helps.

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