The only seed worth harvesting for re use are the straight varieties or the non hybrid types. You must therefore be certain that any pods you remove from the plant are not from an F1 hybrid source as the resulting offspring from such seed can be a right mixture and rarely anything as good as the parent plant.
You may well by now have some vegetable plants in your plot that have gone well past their maturity date. Prior to composting them, why not consider harvesting the seed with a view of re using them next year, after all they are free. The easiest plants to harvest seed from are the peas and the beans but just before you get out there full of enthusiasm, a word of warning, there are a few basic rules to bear in mind.
The only seed worth harvesting for re use are the straight varieties or the non hybrid types. You must therefore be certain that any pods you remove from the plant are not from an F1 hybrid source as the resulting offspring from such seed can be a right mixture and rarely anything as good as the parent plant. F1 hybrids mean that the plant breeder would have used two distinct parent lines for his hand pollination so the resulting seed could be throw back to any parent lines on both sides.
The other very important point to consider is the health of the plant during the growing the season so you must cast your mind back to when the plants were actually growing at their peak and ask yourself whether or not the plants looked healthy. Ideally if you had intended to save your own seed then you should have been monitoring the plants progress throughout the season. For instance, with peas and beans, though it’s important to gather pods with a high number of seed per pod; I consider it to be more important to gather pods from a plant that has consistently throughout the season produced pods with all the merits required to make a top exhibition variety. Once such a plant becomes obvious, it should be marked within the row, I usually tie a piece of coloured knitting wool around the main stem.
Check in particular that no disease or strange growing habits have affected the plants which could mean that they have been affected by some form of virus. Broad beans can be susceptible to the disease Chocolate Spot and the disease can be carried over in the seed and any plant showing signs of this affliction on it”s leaves should be destroyed. Chocolate Spot are small brown spots on the leaves as well as dark streaks along the stem, in a bad attack the spots join together and the plant is killed.
Let Nature Take it’s Own Course
Before harvesting any pods it’s wise to allow nature to take it’s own course so that the pods can harvest naturally on the plant and each species will have it’s own distinct characteristics when mature and the pods are ready for removal from the plant. The pods of broad beans for instance should ideally be dark brown to black and wrinkled which when opened will show seed that have a uniform pale colour with a jet black eye (the part of the bean that was attached to the pod)
The pea pods should be a very pale off white to pale brown colour and should have started to shrivel to such an extent that the pods are papery thin. The variety Show Perfection will have wrinkled peas inside and should be a clean pale green colour with no sign of any brown or black marks on them. Very often powdery mildew will affect the pea plant and pods from late August onwards and a really bad attack can affect the ultimate quality of the harvested seed.
Runner beans pods will harvest to a pale brown and French beans can be either pale brown or even pale white depending on what variety you are saving from.
Once seed are harvested it’s important to store them correctly until required for sowing next year. We have always to remember that dried harvested seed, though appearing as dead material are actually a living cell and should be looked after accordingly. Also rarely are the peas or beans dry enough to store immediately from the pods, I therefore lay all my seed out on a seed tray that’s been lined with soft absorbent paper. The seed tray is then positioned on a sunny windowsill or better still in a dry warm room such where your central heating boiler is or in an airing cupboard until really rattling dry.
Once happy that the seed is dry, they can be kept in a sealed tin or jar somewhere dry and cool, never keep them in a damp environment and most certainly not in a greenhouse. Finally do remember to label the tin or jar, you may well think that you will remember what variety they were but believe me, time can play tricks on you. If you had some exceptional pods of either peas or beans that contained a high count of peas or beans, then these can be kept in the same jar, but in a separate envelope, with the variety and the number of peas or beans per pod clearly marked.
After gathering the pods, don’t just pull the plants straight out of the soil, the roots of these have nodules on them which store and release nitrogen during the growing season so they are best dug into the ground during the Winter months. The tops of all healthy peas and beans make excellent compost and can be added to the compost bin. In my case I prefer to incorporate these straight into the ground when carrying out my winter digging. Indeed Derek Raw, who has won major prizes with his superb large exhibition onions, always used to dig his broad bean tops into the bottom of his onion bed.