Facebook Questions and Answers for the 14th September 2012

Hello Facebook fans, thanks for your questions this week, here are Carly's replies:

Susie Gerrard

I have no fruit at all on most of my apple trees, which are usually prolific and only a teeny crop on my decidedly ill-looking victoria plum! Could all this really be down to bad weather?

Hello Susie. Without further information, it's very hard to say why your fruit trees have performed so badly this year. However, the weather has certainly taken its toll this year on many crops. The warm start to the year looked promising but we had some late frosts in April and wet weather in May and June which will certainly have caused a serious reduction in pollination (particularly for fruit such as plums, apples and pears which would have been in full flower at this time.

Hopefully you will see an improvement for next summer and normal cropping should be resumed. Should your trees not fruit next year then we can safely assume that there is a different cause and you will need to take a closer look at the health of the trees.

Julie Goodwin

Hi VM. We have had tomato blight in our greenhouse this year and all our beautiful tomatoes have rotted and fallen off. We have taken all the plants to our local incinerator, but what's the best thing to clean the greenhouse with to eradicate all traces of disease? Is Jeyes Fluid strong enough? Many thanks in advance.

Hi Julie. The best way to prevent Blight recurring in the greenhouse is to clean it thoroughly, taking particular care to remove all plant and soil debris where spores could overwinter. Jeyes Fluid will certainly help to wash things clean and sterilise the glass, benches, tools and other equipment. It used to be approved as a soil sterilizer too, which could be used on the border soil in your greenhouse. This was particularly useful if you grew the same crop year after year to prevent disease building up. Unfortunately it is no longer approved for this purpose so your best bet is to dig out the top layer of border soil and replace it with fresh, clean compost. Make sure that you ventilate the greenhouse well once you have finished. You might want to consider growing a different crop in there next summer. Crop rotation is a key method in preventing disease build up. If you choose to grow tomatoes in there again next year then try to pick blight resistant varieties and spray them with Bordeaux Mixture throughout the season as a preventative measure.

Fungal problems tend to be exacerbated by humid conditions so make sure that next summer you ventilate your greenhouse well by leaving the door and windows open each day. Watering in the morning will also help to ensure that the greenhouse has a chance to dry out properly before nightfall. I hope you have better luck next year.

Julie Goodwin

Sorry for blagging another question, but will squash, pumpkin and butternuts grow from seeds gathered from fruit grown this season?

Hi Julie. Provided that you are not growing F1 hybrid varieties (which won't come true from seed) then yes you can save seed for next year. Remove them from the fruits and give them a wash before drying them on some newspaper for a few days until they are thoroughly dry. Store them in a paper bag or an envelope over winter - don't forget to label them. Like all seed, they need to be kept in a cool, dry place until you sow them. Next summer it might be worth doing a test sowing first to check that they are viable so that you don't waste time, compost and precious greenhouse space!

Julie Goodwin

Hi VM. I bought some of your Clove Scented Pinks a few months ago and I have grown them on in pots outside. They are now covered in buds and look amazingly strong. Will they be ok to plant out into next year's position now or should I keep them in pots and protected until Spring? Many thanks.

Hi Julie. You could plant them out now if you are short of space but I would recommend keeping them in a cold frame or a sheltered spot close to a warm wall over winter, and then planting them out in mid to late spring.

Dianthus are perfectly hardy but can rot off in cold, wet winter weather. By keeping them slightly protected you will be able to prevent them from sitting too wet. They should get off to a fantastic start in spring once the weather begins to warm up, and by next winter they ought to be well established and able to cope better with adverse weather conditions.

Avril Ferrier

My duo apple tree leaves are turning brown curling up then falling off. The tree is in a container?

Hello Avril. Without further information it is virtually impossible to explain what the problem is with your apple tree. All I can suggest is that you review its growing conditions and make changes where necessary. Container trees are always much more vulnerable to changes in environmental conditions than those grown in the ground.

Is there a chance that the compost might have dried out between waterings, or is the soil sitting very wet? Do you have adequate drainage holes in the bottom of the container? Is it planted in multipurpose compost? If so, then you may want to repot it using a soil based compost such as John Innes no.3 which has a better structure for long term plantings such as trees. At the same time it is worth reviewing the container size. Trees generally require a large container of at least 45cm diameter. Is the tree in a particularly exposed position? Perhaps it would benefit from being moved to a more sheltered spot. Lastly, can you see any signs of pest or disease damage?

I know that sounds like a lot to think about but if you can get the growing conditions right then it's much easier to figure out whether you have a more serious problem. If you have any more information about your tree then let me know and I will try to narrow down the problem for you.

Jane Reavey

Hi Carly, I have south/west facing garden. In the border which gets morning sun/early afternoon sun I can't seem to get anything to grow in it. I have tested the soil which is neutral/alkaline & I've added lots of blood, fish & bone fertiliser to it but still the plants aren't great. (I've planted hebes, dahlias, hardy fushias, hydrangea) Please can you recommend something? I wanted some colour from flowering plants. I'm also about to plant daffodil bulbs but I'm a bit hesitant as I don't want just to get green foliage for spring.

Hello Jane. It sounds as though your soil needs conditioning. My guess is that if it is south west facing then it is pretty dry there. It would be well worth your effort to dig in plenty of organic matter throughout the top 20-30cm of this border. This will help top improve soil, structure, fertility and moisture retention. Organic matter acts like a sponge in the soil, absorbing moisture and holding it in the soil so that it is accessible to your plants. I always recommend using well rotten manure - it's worth asking around as you can sometimes obtain this from local farmers, stables or horse owners if you need a large quantity, although it may mean bagging it up yourself! Alternatively you can buy bags of rotted manure from your local garden centre. Wherever it comes from, make sure that it is well rotted. Alternatively you can use homemade compost from the bottom of your compost heap. Even spent mushroom compost would help.

If you get this done in the next month or so then it will give the soil plenty of time to settle before spring. When you replant, try to choose plants that enjoy hot sunny conditions. I wouldn't waste money on shade lovers such as hydrangea. Go for shrubs such as Buddleja, Ceanothus, Cistus, Lavender and Rosemary. Choose herbaceous perennials such as bearded iris, Eryngium, Geranium renardii and even drought resistant grasses such as Stipa tenuissima which looks stunning when planted en masse! As for bulbs, I would go for Tulips and Alliums which are both sun lovers.

Remember that even drought resistant species need plenty of water while they are young so make sure that you water regularly during the first year after planting until they are properly established. I hope that gives you some ideas Jane. Best of luck with your border.

Linda Teague

Is it too late to take Penstemon cuttings, and how do I get them through the winter?

Hi Linda. It is getting a bit late now but if you can find enough young shoots on the plant then you could still take some softwood cuttings. Take cuttings from non-flowering shoots that are around 10cm (4") long and cut them just below a leaf node. You will need to reduce the leaf area by removing the bottom few leaves. Dip the bottom into rooting hormone powder and stick them around the edge of pots of free draining compost. You should be able to fit several cuttings in each pot.

If you can provide a little bottom heat to get them rooted in then this will help. They will need to be kept in well ventilated, frost free conditions over winter. A heated greenhouse would be ideal. If you have no success then try again in late spring when the cutting material is younger and fresher. Hope that helps Linda.

John Hutchinson

Have you ever used Garlic Juice on Roses?

Hi John, I've not used garlic spray myself so can't comment on the effectiveness! However I have used the crushed cloves as a cat deterrent which worked well. Garlic has long been known for its antiseptic properties so may well be effective against fungal diseases such as powdery mildew and black spot if applied regularly. It's also reported garlic will kill aphids, a major pest of roses but again I couldn't say how effective this is - at home I just blast mine off with a hose or use an organic spray. As it's a cheap remedy it could be worth a try - simply crush some garlic cloves with water (make it quite potent) and leave to stew for a few hours before straining and using. I've not heard of this remedy being available to buy from shops and can imagine it's probably cheaper to make your own! We'd love to hear how you get on with this remedy John, good luck.