Useful Information

RHS AGM

The Royal Horticultural Society Award of Garden Merit (AGM) aims to help gardeners choose the best plants for their garden. You may well have seen the AGM logo. A cup symbol on a plant’s label shows that it has earned the AGM – it's the RHS seal of approval that the plant performs reliably in the garden. 

Awards are usually given after a trial period at an RHS Garden, (often Wisley), and are judged by RHS expert forums. RHS awards can also be given by 'round table assessment'.

Sowing thinly, simply means not sowing too many seeds too close together. 'Sow sparingly' is also used and means the same thing. If instructions suggest that you 'Thinly scatter the seed into the bottom of the seed drill', then don’t be over enthusiastic and scatter too many, as when the seedlings grow, the plants will then need thinning out to the spacing recommended on the seed packet, so that they will grow well.

A finger width apart is usually right for small seeds, although this can be tricky with the very small seeds and some varieties will need further thinning out later anyway.

Thin Out

(or thinning out)

Seedlings generally need to be thinned out when their leaves begin to touch their neighbour. As a general rule, this is when they have sprouted their second set of leaves (these leaves are known as 'true leaves'). Once the true leaves appear, the seedling or plant needs a bit of room to grow properly, and thinning out your seedlings simply means giving each of the seedlings their own room to grow.

Thinning out can also be coupled with 'potting on', which is moving your seedlings from an early seed tray or bed, into a new pot all of its own so the plant can grow. In some cases, like with carrots, thinning out may simply mean removing some of the seedlings from the growing bed entirely, and leaving the stronger seedlings to grow on in the space remaining.

What are F1 Hybrids?

F₁ hybrids, (Filial Hybrids) are largely annual and vegetable cultivars, and are produced by crossing two stable seed lines (called inbred lines) that give rise to especially uniform progeny (or descendants) that possess good vigour, yield and other properties (for example; disease resistance).

It will say on the seed packet if the variety is F1.

Pros: Greater uniformity of flowering, yield, and maturity period. Hybrids often offer worthwhile advantages to home gardeners over other forms of seeds. Greater size and vigour of flowers or produce due to the phenomenon of 'hybrid vigour' (heterosis). Hybrids are therefore more robust and better able to overcome adverse growing conditions.

Cons: Seeds are more expensive. Seeds saved from F1 hybrid plants will not produce plants that are true to the parent type. F1 hybrid seed can be expensive as it has to be recreated by crossing the parent inbred lines again. Self pollination of the parent inbred lines leads to poor quality plants called ‘selfs’. Preventing selfs is complicated and costly which also contributes to the expense of F1 hybrid seed.

When a group of selected plants are grown together and allowed to freely pollinate each other, the seed is said to be open-pollinated. Before the advent of hybrids all seeds were open-pollinated. Open-pollinated seeds are the only option for plants that cannot be easily inbred – lettuces, peas and runner beans for example.

Open-pollinated seed is available for all crops offered as hybrids, but is usually significantly less uniform, vigorous and productive. Open-pollinated seed is relatively inexpensive and can often be readily collected by home gardeners. However, seeds harvested from garden plants will not always come true to their parent, particularly if there is a related plant nearby with which it could have hybridised.

Heritage Seeds (heirloom)

Heritage or Heirloom vegetables or seeds refer to any type of seed that has been grown for a number of years (since 1940 or before seems to be the general rule) and passed down from gardener to gardener.

Heirloom plants are 'open pollinated' which means the plants are pollinated without human intervention, so by wind or insect pollination. Though seed suppliers often sell “heirloom” plants, purists will tell you that true heirloom seeds are generally found through seed exchanges or passed directly down from other gardeners.

Plants grown from these seeds may not be as predictable as hybrid plants, but many gardeners prefer them for their flavour, and many also appreciate the idea of preserving the vegetable’s heritage. Seeds you collect from one year will produce plants with most of the characteristics of the parent plant. And that's key to their survival.

is the process by which a plant grows from a seed. Some seeds need light to germinate, others need darkness but all seeds need moisture, oxygen and the right temperature to germinate.  

Once the conditions are right, the plant inside starts to grow and get bigger. It pushes open the seed coat, a bit like a chick hatching out of an egg. Tiny leaves appear and they push out of the soil. This process is called Germination.

Plants raised indoors or in a greenhouse need to be acclimatised to cooler temperatures, lower humidity and increased air movement for about two to three weeks before they are planted outdoors.

This ‘toughening up’ process is known as hardening off.