Plug Plants - Select the best

Selecting the best plug plants for your garden, part 1.
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1. Always select healthy plants which is true to type

When choosing your plug plants make sure that you look closely at its general health the plant needs to be strong and well-watered, the leaves need to look fresh and free from damage, the stems strong and the roots firm and plump. The plants around your selected plug need to be free from fungal diseases and pests, such as grey mould, botrytis or whitefly. When taking your plug plant from the protected environment such as a greenhouse protect it from extreme temperature changes and strong winds

2. Check the root system

The roots need to be strong and healthy filling most of the plug but without spiralling or excessively spilling out the bottom. The root development shown here is ready for potting on.

3. Dahlia roots

This plug is a Dahlia and eventually will produce a tuber. See our "How to" in the autumn to see how to over winter these.

4. Select suitable pots for potting on plug plants

Select suitable pots there are so many different pots available that the range can sometimes be confusing. The rule of thumb is whatever the size your plug plant is pot it into a pot 1 ½ times bigger so that it has root to develop a good root system without sitting in too much compost that can become waterlogged. For plug plants that you are going to plant into a hanging basket you can use biodegradable pots these are normally peat free fibre pots.

5. Select your compost

A multipurpose compost is ideal for potting on plug plants as it has slow release fertiliser and good water retention. When you take your compost out of the bag it may have lumps in it these must be broken up before you start potting.

6. Get the compost ready for potting

Make sure you work your way through the compost breaking up all the lumps and making the compost viable for potting on. If you leave lumps in the compost as you pot it will create air pockets. Air pockets can slow plant growth by stunting and damaging root development.

7. Now you are ready to pot

This stage is important add a small amount of compost to the bottom of the pot. Just under halfway full.

8. Making sure the plug plant is central

It is important to make sure that plant is central in the pot and upright. This ensures that the roots have equal space to grow and that the top growth grows straight and evenly.

9. Backfill around the plug plant

Carefully add compost around the plug plant, checking that the plant stays in the centre and that the compost goes to the bottom of the pot.

10. Remove excess compost

When potting on the excess compost needs to be removed to prevent this washing off when watering in the greenhouse and becoming a potential area for weed seedling to grow. Removing the excess also ensures that the stem is not buried too deeply which prevents damage to the stem and reduces the risk of it rotting off.

11. Gently firm the plug plant into its new pot

The process of firming the plug plant into the pot ensures that there are no air pockets and makes sure that all the roots are in contact with the compost. Add more compost if required at this stage

12. The final firm

At this stage check that the plug plant is still straight in the pot and not planted too deeply or that the rootball is not to high.

13. From plug to pot

Success the plug plant is now potted on into the next size pot and will now start to grow new roots and shoots.

14. Potted and ready for the next stage

The next stage is to move your newly potted plug plant into a protected environment, such as a greenhouse or a polytunnel. Remember that some garden centres start selling plug plants in January if you purchase at this time of year you will need to provide additional aftercare, such as frost protection, bottom heat and possibly lighting.

15. Watch this space

There will be additional information in part two and three of this series- taking softwood cuttings from plug plants and planting up hanging baskets.
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