🌱✗ Tested and false“Beans and peas fix nitrogen that feeds the crops growing beside them”
Legumes genuinely do fix nitrogen. What they do not do is hand much of it to a neighbour while both are still growing: transfer between living plants in the same season is small and hard to pin down. The substantial nitrogen, tens of kilos per hectare from clover and beans, arrives when the legume dies and breaks down.
Our read That makes it a rotation benefit wearing a companion's clothes. The effect is real, it just arrives a season later than the folklore claims.
What to do: Follow peas and beans with a hungry leafy crop the next season, rather than expecting this year's cabbage to be fed by the beans growing next to it. Leave the roots in the ground when you clear the plants.
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- Legume nitrogen reviewSame-season transfer between living plants is minor and unquantified; substantive nitrogen comes from residue decomposition
“French beans do best in poor soil — don't feed them”
French beans fix some of their own nitrogen through root nodules, but they still need phosphorus and potassium for good pod production. Incorporating well-rotted organic matter before sowing and feeding with a general-purpose fertiliser if growth is poor is the advice. Starving them does not improve the crop.
Our read The nitrogen-fixing ability of beans creates a persistent myth that they need nothing from the soil. They produce some nitrogen, not all, and they still need everything else.
What to do: Prepare the ground with well-rotted compost before planting. Feed with a balanced liquid fertiliser once pods begin to set. Do not pile on nitrogen, but do not starve them either.
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- RHSIncorporate well-rotted organic matter before sowing; feed if growth is poor
“French beans must go in after the last frost or they die”
French beans are genuinely tender and a late frost kills them outright. The advice is to sow under cover in April or direct outdoors from late May once the soil has warmed and frosts have passed. The last-frost rule is not folklore — beans killed by frost do not recover.
What to do: Sow indoors in late April for transplanting, or direct outdoors from late May onwards. In Scotland, early June is safer than late May for direct sowing.
In Scotland: The last frost date varies by several weeks across Scotland. Direct-sow only when your local last frost is past, which in the Highlands and uplands can be mid-June.
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- RHSSow under cover April or direct outdoors late May onwards once soil has warmed
“Dwarf French beans don't need any support — they stand up on their own”
Dwarf varieties genuinely do not need canes or netting, but they can still flop under a heavy crop or in wind. Dwarf beans need no support, but a short twig or stick helps keep pods off the soil in exposed sites.
What to do: Plant dwarf beans and leave them unsupported in sheltered conditions. On an exposed Scottish plot, push short twigs or pea sticks into the ground to keep pods off wet soil.
In Scotland: Wind is the difference. A dwarf bean in a sheltered English garden stays upright; the same plant on an exposed Scottish plot can lean hard, and pods in contact with wet ground rot fast.
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- RHSDwarf beans need no support; use short twigs to keep pods off soil in exposed sites
