Polytunnel Jobs - Month by Month

Polytunnel Jobs Month by Month

March

• Prick out and pot on Tomato Seedlings which where made in February and Early March.
• Sow some French Beans which will start to crop in June. Sow singly into small pots or multiple sow in large pots.
• Sow some Courgette Seeds at the beginning of March and a couple more later on in the month for crops from Mid-May. (Courgette ‘Parthenon’ for the earliest crops as they don’t require pollination for fruit) 
• Sow Basil seeds to produce bushy plants. 3 to 4 seeds per module. Choose a variety like ‘Sweet Genovese’ to grow with Tomatoes and this makes excellent Pesto.
• Sow some Cucumber Seeds for an early crop however they may not survive. 
• Sow Melon Seeds choosing a variety such as ‘Sweetheart’ . Sow six seeds to a 5in pot and keep at 20 degrees Celsius. Seedlings which have emerged from last months sowings should be pricked out into individual 3 inch pots
• Sow Lettuce, Salad Leaves, Rocket and Khol Rabi making regular sowings.  Lettuce can be started off in pots
• Sow a few carrots in a 10 inch pot in the Polytunnel at the start of the month.
• Broad Beans and Mangetout Peas which were put in the polytunnel last autumn or January should have started to rapidly grow. Keep the soil damp and stack up. Broad Beans may need a little help with pollination but the peas should be fine.
• Grapes should be tied back to the support wires
• For extra early strawberries the plants should have been under cover for a few weeks now. 
• Sow Marigolds and Nasturtiums to help keep whitefly at bay. 
• Remove any flowering or bitter crops

         April 

    

• Melon Seeds can still be sown if choosing a fast early variety such as ‘Sweetheart’
• Tomato Seeds can still be sown especially if cherry varieties which will bear fruit in mid to late summer and into the Autumn.
• Basil can be sown if not sown in March. Might be a good idea to make a second sowing in case the others don’t make it through. 
• Florence fennel can be sown into pots put 2 seeds to each before thinning out to leave the strongest, Keep at 12 – 15 degrees Celsius.
• Climbing French Beans can be sown early so that they can crop right the way through the summer and possibly to October. A variety of colours of purple, green and yellow can be sown such as them of ‘Blauhilde’, ‘Neckar Queen’ and ‘Goldfield’.
•  Sow Brussels Sprouts, Kale and Sprouting Broccoli and these can be planted on to be kept outside the polytunnel and be brought back into the polytunnel later on in the year.
• Make a second sowing of cucumbers in April sowing seeds singly ½ inch deep in 3 inch pots. They will grow rapidly and will safeguard against any failures from earlier sowings. An all female variety such as ‘Tiffany’ or ‘Flamingo’ is recommended. Cucumbers can’t usually go out into the unheated polytunnel this month but they may be able to at the end of the month if going into a hot bed and night time temperatures are above 12 Degrees Celsius.
• Pumpkins or Squash should be sown at the same time as the sweetcorn so they can take the space up under the sweetcorn and keep the soil moist as well as reducing weed growth. Sow one seed on its side per 5 inch pot. Varieties recommended are ‘Butternut Squash’, ‘Uchiki Kuri’ or ‘Small Sugar’.
• Harden off any tomato plants so they can be planted out into the unheated polytunnel towards the end of the month
• Dwarf French Beans which were sown in pots in March can be planted out as soon as they have 2 proper leaves however if temperatures are below 8 Degrees Celsius. Plants should be planted in a double row over a trench filled with compost. They bshould be planted 8 inchs apart and 6 inches between each plant
• Courgettes which were sown in March can be planted out in mid-April. A hole about 12 inches square and deep should be dug. Make a short depression around the plant to act as a reservoir.
•   Aubergines and Peppers should be potted on in the heated propagator so they are able to be grown on and so that growth isn’t restricted.
•  Lettuce, Spinach and Khol Rabi which was sown in February or Early March will be ready to plant out when they are about 2 inches high. 
• Leeks and celeriac which was sown in February will have produced healthy seedlings by now so they should be pricked out and potted on into deep tubs full of compost
• Beetroot which was started in cells should be put outside to harden off at the beginning of the month so it is ready to plant outside when conditions allow. They can also be planted in the polytunnel to give an earlier crop
• Feed Strawberry plants to help the fruit swell and have a bumper crop.
• If feeding of Grapes wasn’t done in March it can be done in April. On newly planted vines , all the growing points except the lead shoot should be nipped out and this should be done as soon as the side shoots have made six leaves. 
• Carrots that were sown last month should be growing well in the pot. Make sure they are watered well and fed well to make the young roots swell
• Potatoes which are in buckets need earthing up around the stem as the foliage grows
• If Tomato Plants start to flower mist them lightly with water around midday to help set the first trusses of fruit.
• Mangetout peas which were sown last October should be covered in flowers by now and as they are self pollinating they should start to produce quite quickly
• Strawberry flowers will need pollination and if there are no insects to do the job use a soft fluffy paintbrush to transfer pollen.
• Broad beans will also need pollination and this may be done by using a paintbrush.
• Remove any crops which have finished producing or have gone bitter to make room for summer crops.
• Open the doors during hot weather to allow ventilation and prevent the temperatures from rising much above 30 Degrees Celsius.
• If a new cover is required now is the best time to do it. To get the best possible fit it should be put on a warm, calm and dry day

         May

• Cucumber seeds can still be sown. A variety which is recommended is 'Burpless Tasty Green' and these should be sown singly into 5 inch pots and kept at 15 - 20 degrees Celsius. 
• Basil can be sown for the last time this month
• Sweetcorn can be sown again this month to extend the season. This means the April sowing will be ready and the May sowing a little later. It is now best to grow straight into the ground to stop root disturbance. 
• Pumpkins can also be grown this month. Should be sown in situ and they may catch up with the ones sown in April.
• Dwarf beans should be sown once again as they give heavy crops undercover and are good to have if space permits.
• Regular sowings of Rocket and other cut and come again salad crops should be made to keep a constant supply and will suffer less damage then them outside.
• Khol Rabi should be sown regularly if there is enough space.
• If Tomatoes, Peppers, Cucumbers or Aubergines have not be sown in previous months then young plants can be acquired. 
• Check all plants before going into the Polytunnel to help stop diseases.
• Around the middle of May or after the month's full moon has passed the temperatures should start to settle down. This is the time to start planting into the border soil or large pots and then if needs be cover in fleece. 
• Plant tomatoes into there final home if this was not done in April. Remember to plant some Marigolds to keep whitefly away.
• Remove tomato sideshoots to train the tomatoes up a single stem. Tie tomatoes up every 12 inches or so. Bush varieties don't need sideshoots to be taken off nor do they need tieing up as much. 
• Cherry Varieties of tomatoes usually produce plenty of flowers during May however these may have trouble setting fruit so plants should be misted overhead with a fine spray of water in the morning and evening.
• Feed tomatoes once a week with a high-potash liquid feed such as one based on seaweed for the next few months.
• Sowing of sweetcorn which was made in April should be planted out now. They should be planted 12 inches apart in each direction. If possible put them in blocks to aid pollination and put well rotted manure or compost in when planting them. Also apply a scattering of seaweed on the compost when planting. 
• If Squash or Pumpkin seeds where sown last month they will now be ready to plant out towards the end of the month. One or two pumpkins should be sufficient for 1 polytunnel. To plant a squash or Pumpkin a hole of 12 inches square and 12 inches deep should be made within the block of sweetcorn, and this should be half filled with compost and back filled with soil. A shallow dip should also be made to help with watering. 
• Cucumbers should also be planted out this month. Early May is about the right time to plant them out as March sown plants should be ready. Cucumbers which have been raised in heat these should be hardened off for a week before being planted out. 
• Cucumber plants will need some sort of support and this is best done by putting a stick into the ground and tieing it to this. Tie the other end of the stick to the polytunnel to keep it upright. Twirl the cucumber stem round the stick.
• February sown cucumbers may start to set fruit this month and it is recommended to pick these fruit while still young and only have one or two fruits growing at one time but by June the plants should be strong and large enough to bear large and heavier crops. 
• Harden off peppers, aubergines and melons when the weather has settled and the cold nights have passed. This could well be the latter half of May and even into June. Nights should be above 12 degrees and closer to 15 degrees at night. 
• Aubergines can be planted two per organic growbag or one per 12 inch pot. The plants will love the warm growbag. The bottom of the growbag can also be slit so the roots can then go out the bottom and into the well enriched soil. if the plants are going into the border try to get some well rotted horse manure to put in and then put the plants about 18 inches apart. Water the aubergines at the base of the plant.
• Sweet peppers can produce a good crop when grown into the border soil. They like lots of organic matter and potash. The organic matter will help preserve moisture in the soil and this will help Peppers as they are thirsty crops. If possible dig equal amounts of manure and compost. Add a scattering of seaweed meal to provide potash. Plants should be planted between 18 inches and 24 inches apart. A support stick should then be pushed in to tie the pepper to as it grows. Peppers can also be grown in large pots or grow bags  one per 12 inch pot or two per grow bag. Chilli peppers especially like growbags or pots but these will need regular feeding. The compost should also be kept moist at all times to help ensure good fruit set. 
• Melons should be planted if night time temperatures are not expected to go below 15 degrees celsius. They can be planted in the border soil, three per growbag or one per large pot. If the temperatures are still low keep potting up with little heat. Dig some manure into the soil, then heap up a small mound around 4 inches high so that the melon is elevated a little. This will help provide a better drainage system for temperamental roots. Plants can be planted 12 inches apart if they are to be trained upwards. If the plants are to ramble over the ground they will need a wider spacing of 18 inches.
• Basil plants should be planted out and should be kept as clumps of small plants. Basil should be planted two or three together at 12 inches between each clump. The soil should be enriched with compost or manure and should be kept dry to mimic the drier conditions of the Mediterranean.
• Strawberries should be ripening well this month and there should be plenty of fruit. Remember to water and apply a weak liquid feed when the berries are swelling. If the compost dries out the plants will produce small hard fruit. Always remove any berries that show signs of grey mould.  
• Grape vines should be kept under control with some shoots being cut so the whole poly tunnel is not shaded. Tie the main shoot in as it grows, but allow enough length in the tie so that foliage hangs away from the polythene. Grapes need a lot of water. Roots should be outside the structure so they can benefit from rainfall. Small clusters of embryo fruit should form on the vine during May. The shoots will need to be trimmed during June.
• The first Dwarf French Beans might be ready to pick by the end of May. Pick the pods while they are small and firm and these will then continue to crop for several weeks. 
• If climbing beans where sown in April these should now be ready to plant out. However if they were not sown in April they can be sown during early May for a slightly later crop. A trench should be filled with plenty of compost. Plants should be planted 8 inches apart in a single row. A stick into the ground next to each one and tie the string from this to the roof structure. The beans may need a little help to get started but will eventually twine naturally to the string. 
• Lettuce can be planted under the climbing beans as they don't like too much direct sun. 
• The bolting overwintered crops should now be pulled out and if they are still producing inter cropping should be used until plants are clear. 
• Remember to give adequate ventilation in the Polytunnel to keep it cool but not too cold and not too hot. Open and close the doors as needed to keep a steady growing temperature. Try not to let temperatures go over 30 Degrees Celsius or below 15 Degrees Celsius.
• Keep the borders damp and spray overhead to keep plants cool. If it is really hot, water paths so as the water evaporates it will cool things down.

     June

• This is the time that you should start to think about Autumn and Winter crops. Most sowings for these can be made in July and August so it is not essential to sow in June.
• Lettuce and salad leaves should be sown about every 4 weeks throughout the summer to give a constant supply.
• Sweetcorn can be sown in June to give an extra late crop. These will achieve a reasonable harvest of full cobs during an Indian Summer. Sow two seeds per station directly into the border. Seeds should be sown in blocks allowing 12 inches between each sowing point. The weakest seedling should then be removed at each sowing point.
• Florence Fennel should be sown at the end of the month into deep pots or trays and this will give a late autumn / early winter crop.
• Cucumbers can be sown in Early June. These will grow fast to give a late crop. 
• Many overwintered brassicas do really well under cover and give earlier and cleaner crops than oitside. Sprouting broccoli and Kale can be sown this month and a few plants can be brought and kept in large pots outside the tunnel and then brought in as space clears in the Tunnel. 
• A second sowing of Dwarf French beans can be made if there is enough space within the polytunnel. These can either be sown directly into the ground in a double row, 8 inches apart with 6 inches between plants or into pots which can be planted out in a few weeks time. June sowings will give a late summer / autumn crop.
• Climbing French Beans can still be sown in early June. These should be sown in situ, 8 inches apart in a trench which has been filled with moisture retaining compost. Beans like plenty of water.
• Basil can be sown this month however it is better to buy young plants from the supermarket and spliting them up.
• Khol Rabi should be sown in late June for an autumn crop. These can be sown thinly in pots and then transplanted out as space clears. If space is tight they can be dotted around.
• Beetroot can be started in cells for a winter crop, and these can be planted out in a few weeks time.
• Spray early tomato flowers with a mist of water to help set fruit. Larger tomatoes will usually flower a few weeks behind the cherry ones and the Beefsteak ones may only start flowering this month. If lower leaves overshadow trusses, remove a few to allow light in. The side shoots should continue to be nipped out. Continue feeding the Tomatoes using a seaweed potash feed.
• Keep checking for signs of disease
• Cucumber plants which were sown in Early March should now be cropping really well. Keep picking to ensure that more cucumbers grow. 
• If not already done so, plant out the Sweet Peppers, Aubergines and Melons. Check for Greenfly if leaves are curled.
• Peppers will be growing slow and steady and tall plants will need support so they should be tied in. This will help the plants to support a heavier crop. The first flowers should appear in June. Lightly mist with tepid water and tap the flower stems gently. Remember to give plenty of water so flowers don't start to fall off.
• Aubergine plants which are young may need an extra bit of warmth and this can be achieved by using some fleece. They should also be kept away from any draughts so they should not be planted next to the Polytunnel Door. Towards the middle of the month flowers will start to be produced. The flowers may need a hand with pollination and this can be achieved by using a soft paintbrush. 
• March sown Melons can open the first flowers by the end of May or Early June. Female flowers have small melon-shaped swellings behind them, whereas males are borne on a thin straight stem. The female flowers wont set fruit unless they are fertilized. A male flower should be broken off and the pollen should be introduced into the female flower to make sure this happens. 
• If Sweetcorn plants where put into the ground last month, they may now be 24 inches high. Sweetcorn is a greedy plant and if it is growing slowly give it a liquid feed. Water regularly to optimize the number of cobs per stalk.
• If French Beans where sown in April or May they will be ready to plant out now. The climbing beans position should be thought about so they can form shade for other plants such as lettuce and salad crops. 
• March and April sown Dwarf French Beans should be cropping well by now. The pods should be picked small and they will keep producing for several weeks. Plenty of water will be needed when they are in flower. 
• Climbing French Beans grow rapidly and will twine around a support string once they have found it. 
• Check over established grape vines, there should be small bunches of embryo fruit at the beginning of June. By the end of the month they will have started to swell. If the vine hasn't been mulched with manure then a nitrogen-rich liquid feed should be applied. Remember to water around the base of the vine. 
• Continue to prune grape vines.
• Basil should be ready for picking at the same time the Tomatoes have started to ripen. The top cluster of leaves should be pinched out on each shoot before the flower spikes form. New clusters will grow from the small leaves lower down the stem. Any flower spikes that form should be nipped off. 
• Strawberry Plants will be cropping well by now and they should be kept well watered and fed while fruits are swelling. Ripe fruits should be harvested before slugs and birds eat them and any fruits that show signs of grey mould should be removed.