Thompson & Morgan Facebook Q&A Session 1st April - Your horticultural questions answered.

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Name: Linda Lund

Question: Can anybody tell me if plant-lights are very much better when you grow seeds? I have tried some other lights this year but the plant-growth is little. The plants don’t die but they do not get any size to talk about.

Answer: Hi Linda, I’m sorry to hear your plant lights haven’t worked as well as you’d like. If used correctly grow-lights do normally improve plant growth. Grow-lights should be used as supplementary lighting and should be switched on at the beginning and end of the day to extend the light hours. Natural light will be sufficient throughout the day. Also make sure the plants are given a rest by turning the lights off at night.

It is important to use the right lights when growing plants as normal household light bulbs do not contain the correct light for optimum growth. If you have a proper grow-light (which emits no or low amounts of heat) you should be able to place it 30cm (12in) away from the plant foliage to ensure that your plants are getting the maximum benefit. Make sure the area where you are growing your seedlings is warm enough too, as the lights won’t be as effective without heat for the plants to grow. I hope this helps Linda.

Name: Matthew Eddy

Question: Does T&M have any good tips for supporting runner beans in a potato growing bag please? The variety is Armstrong.

Answer: Hi Matthew, runner beans are very tall plants and can climb up to 3 metres. The normal practice is to put 8 foot bamboo canes or hazel poles in rows or wigwams for the beans to climb up. I think the best way to support your beans in a potato grow bag would be to create a wigwam, although you will probably want to use shorter canes unless the beans are going to be in a sheltered position (also think about how you are going to reach them!). Allow 1 or 2 plants per cane. Once the bean plants have outgrown their supports pinch out the growing tips to prevent further climbing (your bean plants will produce side-shoots once pinched out).

Name: Matthew Eddy

Question: I ordered your apricot begonia corms, planted them according to the instructions. I have seen no growth yet! Am I doing it wrong.

Answer: With regards to your begonia tubers it can take some time for Begonia tubers to start sprouting. Tubers should be planted just below the soil surface. Make sure the room where you’re keeping the tubers is warm and keep the soil just moist. Be careful not to over-water your tubers as they are susceptible to rotting. If you have any doubts you can always give them a gentle squeeze to check if they still feel firm. If you have followed the instructions provided then you should start to see some growth soon, unfortunately you do have to be patient with begonia tubers! Good luck Matthew.

Name: Matthew Eddy

Question: How high does aquadulce Claudia and the sutton broad beans grow to please? Also how high do feltham first, kelvedon wonder and hurst greenshaft peas grow too and which is the best way to support them?

Answer: Hi Matthew, ‘Aquadulce Claudia’ grows to 1 metre in height and ‘The Sutton’ is dwarf, only growing to 30cm (12in) height. ‘Feltham First’ and Kelvedon Wonder’ are quite dwarf and only reach about 45-60cm height whilst ‘Hurst Green Shaft’ is slightly taller at about 75cm high.

The best way to support peas and dwarf varieties of broad bean such as ‘The Sutton’ is to use twiggy sticks. Push these into the ground around your pea plants once they start to produce tendrils - as the peas grow their tendrils will wrap around the twigs. Alternatively you could erect bamboo poles in a row with netting stretched between them, before sowing or planting your peas.

Broad beans do not have tendrils and the stems are quite brittle so the best method of supporting tall varieties is to use bamboo canes with wire or string stretched across them at intervals up the canes. Place a set of canes and wires either side of your broad bean row to support the plants on both sides. You could also stretch netting between the bamboo poles if you don’t have string or wire. Good luck Matthew, let us know how you get on.

Name: Shelley Smith

Question: hi i have a strawberry planter bag thats half full is there anything else that i can use the compost for please i have done 6 strawberry plants so thats enough for us. Thankyou

Answer: Hi Shelley, the remaining compost would be ideal for a number of small vegetable plants. You could try growing lettuce, salad leaf mixtures, dwarf beans, dwarf runner bean ‘Hestia’, mangetout peas, radishes, beetroot, herbs or trailing/bush tomato varieties such as ‘Losetto’, ‘Cherry Cascade’ and ‘Tumbling Tom’. If you were to grow lettuce I would recommend ‘cut-and-come-again’ varieties such as ‘Salad Bowl’ to make the most of the small space available. You could even have a mixture of trailing flowers with your vegetables for added interest! I hope this has given you some ideas Shelley.

Name: John Fowell

Question: Hi all :) Question for Sue: I have violas in full bloom, a cherry and damson bursting forth and some over-wintered Pelargoniums about to flower. Even though it's only the end of March/beginning of April, shall I start to apply feed? Thanks.

Answer: Hi John, yes it is certainly the right time to be thinking about feeding your plants for the season ahead! Feeding should begin as soon as plants start into active growth. Your Violas and Pelargoniums will benefit from a high potash feed now to ensure they keep flowering well. Your cherry and damson trees would benefit from an application of a slow-release fertiliser around their base along with a mulch of some well rotted manure, garden compost or recycled green waste. When you mulch your trees make sure you don’t mound the mulch up against the bark, leave a 10cm circle free of mulch to prevent the bark rotting. I hope this helps John.

Name: Valerie Williams

Question: I'm looking for hardy perennials to form a hedge - any advice

Answer: If you’re looking for hardy herbaceous perennials (that die back in the winter) to form a hedge you could try Echinops bannaticus. This grows to about 1m tall with spiny grey-green leaves and spherical blue flowers in late summer. Another good plant to try would be Eupatorium purpureum (Joe Pye Weed) which can grow up to 2m tall but has very stiff stems so will not flop over. It bears pink-purple flowers from July until October. Other tall and bushy herbaceous perennials that would make a good screen would be Filipendula camtschatica (Giant Meadowsweet), Rudbeckia laciniata ‘Goldquelle’, Helianthus ‘Monarch’ (Sunflower) and Macleaya microcarpa ‘Kelway’s Coral Plume’. For an evergreen option you could try varieties of Phormium tenax (New Zealand Flax) which are very architectural.

If you’re looking for more shrubby plants to form a hedge you could try using shrub roses (not hybrid-tea or floribunda types). If you don’t need much height then you could use Lavender as a low-growing evergreen hedge. Other shrubs good for hedging include Rosemary, Berberis, Box (Buxus), Privet (Ligustrum), Pittosporum, Eleagnus, Euonymus, Hibiscus and Choisya. I hope this has given you some ideas to start!

Name: Jo Moore

Question: I want to grow a climbing rose on my front porch. There is no usable soil in the front yard. How big a container would I need to grow a climbing rose long term? I want one that will get about 8ft tall.

Answer: Hi Jo, you’ll need a fairly large container for the best performance from your rose – aim for a container that is at least 30-45cm (12-18in) deep. This will provide space for good root growth and will also provide a stable base for supporting such a tall climber. Make sure you use loam-based compost to fill your container, such as John Innes, rather than multipurpose compost. If you’re using a wigwam-style support, try training the stems around the outside of the support so they lay in more of a horizontal position. This will encourage more flowers than if the stems were left to grow upright.

Provided you feed your rose each spring with slow-release fertiliser and keep on top of watering during dry spells, your rose should last for many years in a container. Good luck Jo.