Since last month, most of the coriander plants with severed roots* have caught up with the control (red). It looks as if severing the roots - thereby inducing earlier lateral root production - can substantially improve growth.The pot was left without water for a short period, so things have not been ideal. But, provided the plants do not run to seed, it will be interesting to see what happens from now on.
IMPLICATIONS FOR POTTING UP
Many growers pot their plants up into larger pots as soon as the primary root(s) encircle the base of the pot. Instead of this, why not break the root(s) off. The plant could then be left longer in its pot and produce a better root structure which should ultimately lead to a stronger plant.
I have always teased away excess roots encircling the pot of pot-bound plants, then broken it off before re-potting. Until recently, I thought everyone did this.
IMPLICATIONS FOR POTTING DOWN
Who said you 'can't squeeze a quart into a pint pot'? Not me. Not any more. What I mean is that it might be possible to quite severely trim the roots and re-pot a subsequently improved plant into a smaller pot. Of course, exhibition growers have done this for years. I am beginning to see why.
* plants with roots severed half way down the pot, and below
8 comments:
Hi Jimini, it's me Diana again. I took a gamble with my very tall Coriander plant and tried the repotting method you suggest here. Wow, it really works. Basically repot it back into its original pot. Growing very well now, has about 16-20 sprays of flowers. Trying my hardest not to water it too much. Tempted to water with Seasol every now and then. Chewed off plant still growing slowly... haha.
Diana, it's good to hear from you again. I'm really flattered you took such a risk with your coriander (I wouldn't have). Seems like a wonderful plant to have recovered like that within two weeks. Impressive. Could you tell me more about what exactly you have done and how you normally grow it. It's obvious you are an accomplished coriander grower. I don't actually know much about it, but it fits into learning to water plants quite well. However, I really would like to know more.
Anyway, this is what I think: If it's so large, it should have enough roots not to have to worry (you, I mean, not the plant) about over-watering. Plant leaves, stems and fruits (coriander 'seed' is a fruit) actually grow fastest when soil or compost is at 'field capacity'. i.e. water left after soaking and draining. Water is 'looser' then, easier to take up. And oxygen pulled down into pot by draining (water acts like a plunger as it sinks down) allows roots to take in water and nutrients efficiently. If you want growth (also fruit growth, once set), watering every day, at this stage, might be the answer. Witholding water after a soaking is good for growing roots and flowers (plant thinks it's about to die, so reproduces like mad) - seems to give a stimulus so plant knows to grow roots next time sufficient water comes, if that makes sense (see recent geranium post (29th May) on root growth after a watering/drying cycle). Root growth is hormonal, controlled by auxins (growth hormones) among other things. So stimulus should only need be given once....
Seaweed extract available in UK as a tonic (eg 'Maxicrop') or as liquid plant food (I'm presuming 'Seasol' is one of these). Seaweed tonics can be given quarter strength at every watering, right from the off (even in new compost), and will really strengthen root growth (haven't actually done this myself, but know a man who has; although have found them wonderful on flower colour). Similarly, all plant feeds (including seaweed feeds) can also be given quarter strength at every watering, omitting every fifth one to give any unused salts chance to wash away. But these feeds need to be started a little later, once feed in compost used up. All seaweed feeds are rich in micronutrients, and wonderful for plants and their health, as I know you know. So you're right to think about using either one (tremendous perception there - the best growers grow by instinct). Should do plants a world of good ....
Chewed-off plant will still have a good root structure, so should be growing extra fast now. It might benefit from a feed higher in nitrogen (eg N-P 3-1 (even dilute lawn feed, but be careful!)). This will improve growth rate and leaf size. Hope you can understand even a word of this. P.S. also hope rampaging rabbit is now well-muzzled!
hi jimini, thanks for the reply. nah, not an accomplised grower, just got lucky. had 3 lots died on me prior to this. in fact, i think i might have said too soon about the coriander, as it is flopping quite a lot of late. had to get stakes to support it. the weather in australia is just starting winter now, so i'm not sure if that's having an effect on it. the 2 main plants have grown somewhat weirdly; stems are quite wavy instead of straight, i guess due to the trauma of being repotted, and the smaller plant that was starting to stem up is now withering a bit.
i'll keep you updated on this. praying that they'll survive now that it's quite mature. the chewed off one is withering and browning up, so it's going to heaven. lol.
Diana, thanks for putting me more in the picture. Floppy leaves in hot sun are usually due to lack of turgor pressure in cells caused because plant is losing water faster than it can be replaced by roots. This is not so bad as it sounds and in some ways is a good thing as it stimulates root production. Provided compost is not bone dry, suggest spraying leaves with water and moving pot into shade (can often just cover with horticultural fleece or newspaper) till things return to normal. This will cut down water loss and give it chance to recover. Where many growers go wrong is to apply too much water to hot roots (also check roots aren't cooking), thereby suffocating them to such an extent that they cannot absorb water.
Plant could also be pot-bound. When potting down (placing plant into smaller pot), must ensure there is some fresh compost around roots. Sorry, should have made this clear. If shading does not work, suggest you pot it UP into a larger pot, taking care not to damage roots - this is how I recommend you grow coriander when growing for leaf rather than 'seeds'.
Damage (usually dying back of some sort) to a part of a plant is usually because one of its roots has been damaged. This is because different roots often supply different parts of the plant with water. Not much you can do about this now.
The thing to do is save the plant and get the 'seeds'. As far as season is concerned, coriander is an annual, so should set seed, disperse them, then die back. Annuals usually turn brownish and brittle at this stage, so obviously are dying. But they normally remain erect so they can disperse their seeds. I'm afraid to say I don't know what coriander does at this stage, because I only grow it for leaves, so have never let a plant go to seed. But I do know that coriander can be grown all year round, though light not really adequate in UK winters (see 'Coriander Canary Detects Low Light' January 6 2011 ).
Following our discussions, I have trimmed roots on an old coriander 'Multi-Plant' laying around under bench. Compost had gone really dry, so might be problems. But will be interesting to see what potting up does. Posting details this week.
Thanks again for your help, Diana. I really appreciate the feedback. Hope things improve soon.
hey me again. thanks for the tip, although i think that australian summers might be not to great for coriander, that's why it's was doing much better when i grew it in autumn. but now that it's winter, what would be your advice to help this mature plant not die on me? >.<
don't know if the coriander would tolerate another repotting at this stage since i suspect that it's damping off. the stem still seems to be quite strong but it's just the top feathery 'branches' that have gone curly/wavy and flopping by heaps. i really really hope it doesn't die on me. 60% of flower buds are still not mature, and only 1 of the sprays has just withered its petals. i believe that i won't see any proper fruits till possibly 4-6 weeks, provided it's still alive. will keep you posted.
ps: is there a way i can send a photo of the plant to give you a better idea what the plant looks like now? thanks jimini.
Diana, Think I understand what plant looks like; so don't need picture at this stage. Need to elimiate a couple of things:
Have you used any hormonal weedkillers (especially 2,4D) close by? Some plants are ultra-sensitive to these (especially roses).
Could plant be overwatered? This is the classic trap: plant starts wilting, so water poured in. Suggest remove from pot and check. See all 'turbo pot dryer posts'; these really work very well. Place kitchen towel over inverted plant pot and stand plant on it.
If you have had aphid trouble, might have left a virus. These often cause wilting.
'Damping off' could be caused by several fungi, most of which work in cool damp conditions, though not necessarily. Botrytis can be very prolific in warm damp conditions. Suggest you dry everything off as much as you can and introduce as much fresh air as possible. Botrytis thrives in still, damp air. If you look at winter fuchsia posts, you will see I have been plagued by this disease all winter - and even recently in summer. Myclobutanil is an effective systemic fungicide, but only seems to work (although this is not confirmed and never tried on coriander) BEFORE INFECTION. Alternatively, 'Dithane' is an extremely effective contact fungicide. But these MUST be given before infection.
Don't think above will be much help. But best thing to do is keep plant cool and airy, after checking compost not soggy. Sometimes miracles do happen. Thanks for your feedback, Diana. Note coriander post on blog this week.
hey jimini, looks like the coriander is finally recovering, though really slowly due to the winter season. i've basically tied a ribbon around the branches to storp them from snaping off, got rid off the 'damping off' plant, and left it on the windowsill as is. had a look at it this morning and it seems alright; the flowers are standing erect though the branches are still wobbly. i think i'll restrain from watering it a couple more days just to make sure the roots span out.
never used commercial pesticides before, only home remedies like detergent/oil/bi-carb/chilli-garlic sprays. a greek fella here uses it like that here, works a charm.
well the experiment was really scary, but i guess you don't know till you try. had a look at your new post. might try that next time when i get some new plants. too scared to try on this one now. lol
Diana, it's not just your plant - mine is starting to topple over now, a couple of weeks after re-potting. It started with two outside stems (there are 20 plants in the pot), then all were down this morning. But it's toppling (like trees), not wilting or shrivelling. I think it's just top-heavy. After all, it's grown very quickly; and the new compost has produced long growth with some of the internodes being 5cm (2 inches). The stems seem very healthy, and it's flowering well. However, there are some brown bases on some stems, which I'm not too happy about. No sign of fungus or any disease, though; and brown patches seem quite firm. But it could still be some sort of stem rot. Hope it's not. Only time will tell.
New compost contains too much nitrogen for flowering plants. Would have been better to have washed out feed from compost first, then fed with tomato feed (N-P; 3-1). The extra potassium would have created more fibrous and shorter growth, making for a stronger plant. It's a bit too late for this now.
Have only tied up half of fallen stems. There could be an advantage to having horizontal stems (kept off ground), because it removes apical dominance, allowing side shoots (with flowers, hopefully) to form. Will keep you informed.
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