Growing under glass or polytunnel

You may use your greenhouse or a polytunnel as an outdoor classroom; however in order to utilise the space most effectively leave enough room for growing crops or plant propagation. The size of your greenhouse will restrict the number of children able to work inside so you should consider the maximum you intend to have working at any one time.

Which crops do you want to grow?

• Certain crops like tomatoes, cucumbers, grape vines, ornamental gourds, aubergines and melons will grow more successfully in a greenhouse. They will occupy your valuable greenhouse space across the summer months and will need watering during the holidays. It is also important to be on the look out for pests such as spider mite or aphids and control as necessary.
• Extend the growing season for edible crops. Early harvests of carrots, beetroot, radishes, potatoes and other crops can be achieved using a greenhouse by growing direct in the soil.
• Take cuttings from herbs and sow seeds in trays and pots for early tender crops such as sweet corn and courgettes. 
• Decide how many of each edible crop you want to grow and if you have space to do so either in the soil or in pots ready to plant out. It is a good idea to allocate space for each crop on a plan at the beginning of the growing season.
• Consider building slightly raised or edged beds in a polytunnel, this will create a pathway which eveyone can see.

Plant propagation and growing on.

If your greenhouse or polytunnel has benching in it you will probably want to use it for growing seeds and cuttings. 

• Hardy annuals and vegetable seeds can be started off earlier in glasshouses than direct in the soil outside.
• Follow the instructions on individual seed packets for growing indoors, but remember early in the season the temperature will be cooler overnight if the glasshouse or polytunnel is unheated.
• If you are going to be doing a lot of propagation and have an electricity source, consider obtaining a heated propagation case or bench to provide extra heat for your seedlings and cuttings, this will expand the range you can grow.
• Horticultural fleece is useful to cover the seeds or cuttings as it will insulate and provide a few degrees extra warmth. Use it when seeds are freshly sown, pricked out or for new cuttings to reduce transpiration.
• Once seedlings have been pricked out or cuttings potted on, the greenhouse or polytunnel is the place to grow the plants on until it is time to plant out (or the danger of frost has passed).
• Cover a floor area of the polytunnel or greenhouse with a weed suppressant for good hygiene and 'line' the plants out in rows. Remember to leave a small pathway to allow for access when watering.
• Once the sun is stronger remember to ventilate the greenhouse or polytunnel during the day. Greenhouses may also need some shade protection to stop young plants from being scorched.
• You may wish to use a greenhouse or polytunnel to store tender plants over winter. Wrap or cover plants with horticultural fleece and reduce watering for extra protection.