Pest and Diseases A list of common problems

Never had a lot of problems with asparagus. It can be difficult to transplant as it is purchased “bare rooted” not pot grown. My garden is in the North West of England and wind can be a problem, blowing the feather like stems over and breaking them off at ground level, so some support may be necessary.

These love heat and tend to sulk if the temperature is low or fluctuates. Because of the warm surroundings white fly and red spider can be a problem especially if you are trying for organic status. Try to damp down as often as possible.

A very under appreciated root vegetable, possibly one of the most rewarding pleasures of growing your own veg is to pop a gobstopper size baby beetroot, fresh boiled and peeled into your mouth whole, and devour with the greatest of joy. It is never much of a problem to me – the only possible drawback is it’s tendency to bolt (go to seed) in adverse conditions, but choosing the right variety and looking after the plants with plenty of water in dry conditions seems to solve the problem.

Probably, the most resilient of all beans grown for human consumption. You can always rely on them for some kind of crop whatever man or the weather throws at them. Black fly attack the tops of the plant, especially late sown crops, so sow early (see my October video) and when the plants have reached a good height with plenty of pods on, nip the top three or four inches out to deprive the black fly of a starting point. One other thing - don’t let the pods get too large. Pick them young when the individual podded seeds are about the size of your thumb finger nail.

To save space I always grow climbing French beans – eight plants grown in the greenhouse supplies me with tasty beans all summer and every Sunday mid-summer I freeze the weekly surplus to provide beans until the next years crop. Flowers not setting can be a minor problem, but a regular spray with the hose pipe helps. Don’t leave very large unpicked beans on the plant because as soon as they set seed, they will stop producing pods, so pick young. They are hungry so I give them a top dressing of well rotten manure half way through the summer ( this also acts as mulch to preserve moisture).

The same advice as French Beans, but Runner Beans are much more prone to not setting, especially in dry weather. They are best sprayed with the hose pipe in the evening and keep the roots moist. Definitely pick when young, because when mature the pods get stringy just like eating wire wool. Quite tender, don’t be in a rush to plant out too early.

To save a lot of repetition I am going to do quite an extensive coverage of problems when we get to cabbage. This is because the problems encountered with cabbage are relevant to most of this family of plants (brassicas). This includes, cabbage, sprouts, caulies, calabrese, swede and of course brocollie. Brocollie matures approx. April and so a lot of summer pests do not bother it. (cabbage white butterflies, white fly etc) and so the only precaution I would suggest, is to make sure the plants never work loose in the wind. Support with bamboo canes if necessary and pick the shoots nice and young to encourage the production of more shoots along the stem.

My plot is in a windy area and so I support my sprout plants – this year they grew to approx. 4 feet high. Thick bamboo canes with regular hemp string ties works for me. Cabbage white butterflies can be a real problem later on in the year as they get too tall for the net covers , which I prop up on stilts until they get too tall. After this, picking off the caterpillars and disposing of them by hand helps. An old remedy of watering the foliage with soapy water (soap not detergent) works to a degree. In hot summer I have had problems with aphis and white fly attacks and because sprout plants are so big and complex in structure I have reverted to systemic pesticide sprays. Although I try to grow totally organic I don’t have a problem with the odd use of these pesticides as a last resort.

Although easy to grow and very underrated cabbage can give us a few minor problems which apply to most brassicas (cabbage family). Caterpillers of cabbage white butterfly are a real nuisance. I grew all my brassicas under frames made from strip timber and covered in ½” x ½” plastic mesh – this easily solves this problem.

Cabbage root fly is a fly that lays its eggs in the soil near a young brassicas stem. When the eggs hatch the resulting grub travels to the stem and burrows inside eventually killing the plant. By stopping the fly depositing eggs near to the stem this problem can be avoided. Simple collars of felt or plastic can be purchased or made - slipped over the stem thus stopping the fly laying near plants.

Club root is more serious. It is a disease which affects brassica roots, killing them and resulting root stump looks like a club. Unfortunately, once you have this problem it can stay in the soil for a long time and the infected area cannot be used for brassica production. Various treatments are available and some varieties of plants show resistance to club root.

Unfortunately carrots suffer from a real problem - carrot root fly. I have tried everything – inter-planting with strong smelling plants – marigolds, onions etc. Surrounding the plants with high barriers and resistant varieties but the only 100% guarantee of success is with a cover of a very close mesh. Mine is approx. 18” high made from strip wood and covered in fly proof mesh available from garden centres – root fly – no problem. Carrots can be difficult to germinate in cold wet springs sometimes taking more than one sowing, so timing is important. Don’t be impatient – or do as I do watch the videos. I have fresh carrots available 12 months of the year. Lastly, don’t manure the ground in which carrots will be sown otherwise you will get disorted double or treble misformed roots. (Fang roots the post name).

Same problems as cabbage. Cut the central curd or flower and leave the main stem to supply lots of mini shoots – much nicer than the large central flower.

Same problem as cabbage. When the curds are maturing snap a few leaves and fold over the white curds to prevent the sun yellowing them.

Same family as carrots and so carrot root fly can be a problem. Celery needs copious watering on a daily basis – I think naturally they grew in wet conditions. I lost a complete crop one year to a fungal disease probably blight, but I scrapped the lot as soon as I knew all hope was lost and sowed more immediately. These produced small plants but I used the stems and leaves for flavouring even though immature and I hardly missed the main crop. Bolting going to seed can be a problem in hot dry summers – so as I said earlier plenty of water.

A lovely crop to grow. I find two or three plants is ample – never grown just one plant – if it dies it is too late to replace and that is courgettes over with for 12 months. In the North of England where I am it is cold in the Spring so they need plenty of TLC and protection until flowering time. I grow mine in cold frames and remove the lights when they grow their first flowers to allow the insects to pollinate them. Pick young to ensure prolonged supplies.

Hard work in the early stages of growth. They are prone to strange diseases like verticileum wilt and fusorium – far too complex to discuss, in a brief journal like this. Let’s just say that they can be growing perfectly and one day you walk into the greenhouse and they are drooping as if they are thirsty – watering only makes the matter worse and they are doomed. Scrap them and start again if time permits. These problems are nearly always down to cold damp conditions either in the soil or atmosphere. Until the plants are about 12 inches high go steady on the watering and keep them warm and out of draughts. As a backup I always grow two plants to maturity in case I lose one and to produce two fruiting plants. I begin with four seedlings and discard the two weakest. They love heat and red spider and white fly can be troublesome but as the plants get bigger regular spraying with the hosepipe and damping of paths helps to provide a humid atmosphere which the pests dislike.

Easy to grow – choose good bulbs to start with and plant the largest cloves (see video) The big problem and I seem to have it every year is rust. It appears as rust on the leaves with tell tale pustules right at the end of the growing season when the bulbs should be having a growth spurt. It is air borne so there is not much you can do about it, and it can be made worse by having infected onions or leeks or any of the onion family plant adjacent to the garlic. Always remember rust can only survive on growing plant tissue and so if you get rid of the infected plants you eradicate a source of infection. I always allow plenty of room between my plants to encourage air flow because this kind of disease thrives in warm moist conditions. When watering late in the year try not to wet the leaves.

It was only when I started to write these notes that I realised that I have never seen aphids on the strong smelling herbs like rosemary, lavender, sage etc. Perhaps the pungent oil in the plants stops the beasts from sucking the sap? I think it must help as I never seem to get a lot of problems with herbs. Here is a good little tip - When growing any plant just take a minute to visualise where it grows in nature. Imagine the Lavender growing in warm dry Provence and then try to create the same conditions in your garden. So with herbs provide well drained soil with grit mixed in and make sure the soils not rich. Locate the herbs in the warmest sunniest spot available – perfect! One last note Basil is always tricky in the seedling stages and hates cold and damp – so plenty of TLC.

Very hardy winter maturing never a problem. I grew mine close together to produce lots of small leeks , so you are not leaving half used leeks in the fridge. Rust can be a problem but not to the same extent as Garlic. Just nip off infected leaves and don’t put them in the compost heap. Get rid of any badly infected plants to discourage the spread of the disease. Sometimes leeks bolt (go to seed) cut off the flower spike and use the plant a.s.ap.

LETTUCE Easy. Slugs are always a problem – if you use pellets try to ensure wild life can’t get at them, otherwise hand pick and destroy the slimy creatures. Aphis are never far away - I don’t bother just wash the leaves in salty water before use.

Rust can be a minor problem -be vigilant as with Leeks. Try not to give the plants too many shocks in their life eg. Drying out as this can lead to bolting later on in the growing cycle. With set grown plants you can purchase heat treated sets which are not as prone to bolting as normal sets. Talking of sets – birds can be a problem pulling out the sets by the straw like top. Best to put a net over until they are rooted. White rot – is the only real problem with onions which is soil borne and has no cure. If your soil does become infected you will not be able to grow any onion family plants on that area ever again. Good hygiene in the garden is essential and constantly rotating crops. Ideally don’t grow onion family plants on ground that has had them in for 3 years.

a member of the carrot family so beware root fly. Canker can be a problem but a lot of new varieties are resistant so choose your seed wisely. Incidentally, parsnip seed doesn’t keep well so only purchase enough seed for one year at once and discard any that you don’t use. Parsnips do taste better when they have been frosted (the cold turns the starch into sugars) so it is not an old wives tale.

If you looked in a reference book at the ailments that can affect peas you would probably never grow them –there is fungus, bugs,maggots,weevils etc but without being smug I have only had one or two problems. (I hope I don’t regret saying that.) The summer of 2018 was unseasonably hot and mildew brought an early end to my garden peas and sweet peas. Mildew appears when it is hot and dry and the only thing you can do is regular watering and spraying with the hosepipe. At the sowing and seedling stage mice and wood pigeons can devastate a crop so take precautions. Pick the pods young to encourage new ones to set and always make sure you have got a good supply of fresh mint to go with them in the pan. I add mine when they are cooked and drained and leave them for two or three minutes, shaking and stirring them occasionally. Take out the mint – add a knob of butter – delicious!

Early growth seems painfully slow with peppers and chillies. They crave heat and with home grown facilities we just can’t provide it to a high degree. I grow mine in pots and from the initial thumb pot to the final large pot I repot them perhaps about four times, this gives me a chance to get fresh nutrient rich soil round their roots which boosts early growth. Good glasshouse hygiene is essential as they suffer from the same ailments as most greenhouse plants. Keep your eyes open for red spider and white fly. When mature the plants benefit from support of bamboo canes or sticks as the stems are very brittle and can snap off when the fruit gets large and heavy. You will always lose a few immature fruit to botrytis (fungal rot). Just snap them off cleanly as possible, discard them and the remaining fruit will swell to replace them.

As I have already said I am self sufficient in potatoes 12 months of the year so I need to keep my eyes open continuously to protect my crop. Blight is the biggest enemy of potatoes and is at it’s worst July-August especially if it’s a damp humid year. If you spot the tell tale black spots on the leaves and they seem prematurely yellow, it’s probably blight. Don’t delay, cut off the foliage (haulms) and dispose of it. Don’t compost it – dig up your crop asap on a dry warm day. Leave them to dry then dispose of any black or soggy potatoes – bag the rest and check them in storage for the first few weeks discarding any soft or unusual ones. There are more and more blight resistant varieties available now, so if you do get blight this may well be your answer. Always rotate the crops. A three year cycle is ideal but with my small garden I have to make it a two year cycle. This helps to avoid eelworm which is really bad news. This microscopic worm (nematode) can stop in the soil indefinitely. Slugs and wire worm take their toll but I think good deep digging exposing the soil to frost in the winter helps to minimise damage. Scab is bad to look at but can be removed when peeling the potatoes with no detriment to the potato. Manure is supposed to cause scab and a lot of people don’t use it with potatoes, but I do and things are not too bad. Some varieties are more prone than others so check when obtaining seed potatoes – Maris Piper is a disaster for scab.

I have been growing my own radish since I was four so I have a soft spot for the little beauties. They will never let you down – they will grow anywhere and apart from the odd slug hole they are not a problem. Harvest them when they are young don’t let them get too large as they become “wooden” and taste like hot coals. A good first crop for any aspiring gardener to be!

Much the same as radish except I was a bit older when I first grew swede. Pick a yellow fleshed old fashioned variety and ignore what it says on the packet. Grow them close together – don’t sow until May and aim for lot’s of tennis ball size roots, so that you use the complete swede when cooking – you can always pick two if one isn’t sufficient. Water well in summer and grow them as quickly as is practical, to produce tender sweet roots that are not “wooden”.

Where do we begin – such a complex and broad spectrum subject. I’ll keep it brief and not too technical, but from sowing to picking the last fruit in Autumn they need constant attention. When you sow them don’t cover the seed they need light to germinate. Prick out the seedlings into individual cells or small pots. Use sterile compost at the same temperature as the greenhouse and don’t oversoak them. Grow them on and never let them catch a chill, if they do, they go blue, scrap them and start again, they will never be any good. Give them as much light as possible. So they don’t get drawn, the first truss of fruit needs to be as near the soil as possible. Ventilate whenever possible to keep the air moving and if in grow bags feed when the first fruit is the size of a small marble. If greenhouse grown support with hemp string from the greenhouse roof – remove side shoots carefully. If they are large cut them out with a sharp blade – don’t leave any stringy bits or ugly wounds as this is where botrytis strikes. A wound of this type when infected will result in the death of the plant. Botrytis spores get in the air and if they land on a droplet of water on the fruit they mark the fruit and spoil the look of it. (This is called ghost spotting). If the plant when growing strongly seems to be thirsty but no amount of water can perk it up, then it probably is suffering from a think call Wilt. If it is not too late in the year remove the plant and start again. In August you won’t really want anymore fruit setting as it will be too late to ripen it so I nip the top of the plant out and it will turn all its energy into swelling the existing fruit. Throughout the summer don’t waste any surplus fruit let them ripen to blood red , pick them, skin them by putting them in pan and pouring boiling water over them. Leave for a couple of minutes pour the hot water off and run cold water over them – the skin comes off easily. Chop them up roughly and gently boil the fruit for half an hour or so to produce a pulp – cool in small plastic containers and freeze. This is good for at least 12 months and use it for pasta sauces and chillies etc.