If your soil is very fertile you won\u2019t usually have to even think about additional fertilization of the growing crop. However there are situations when growing crops will benefit from a quick boost of a specific nutrient. In such cases you can use some form of post planting fertilizer. Reasons for fertilizing after planting include:<\/p>\n\n\n\n
\u2022 It can help you get\nreasonable yields when you are first establishing a garden and the soil isn\u2019t\nvery fertile. Fast growing crops such as radish and spinach may be fed weekly and will greatly benefit\nfrom the steady and continuous supply of nutrients. <\/p>\n\n\n\n
\u2022 It can help\nover-wintered crops get off to a fast start, by giving them a shot of nutrients\n(especially nitrogen) when the soil is cold and nutrients are least available. <\/p>\n\n\n\n
\u2022 It can be used to give\nan easily absorbed boost to rapidly growing plants, or those that have been\nstressed by transplanting, harvesting or pests. <\/p>\n\n\n\n
\u2022 It can be used to help\nmaximize yields by giving plants the nutrients they need at critical times in\ntheir development (such as when food storage organs are enlarging). <\/p>\n\n\n\n
\u2022 It can help long\nseason crops get all the nutrients they need, even after they have exhausted\nthe locally available nutrients. <\/p>\n\n\n\n
\u2022 It can be used to save\na nutrient deficient crop, by supplying the necessary nutrient in an easily\nabsorbed form. <\/p>\n\n\n\n
Foliar fertilizers<\/strong><\/p>\n\n\n\n Foliar fertilization\nconsists of spraying a dilute solution of liquid fertilizer onto the leaves of\na plant. It works because plants are able to take up small quantities of\nnutrients directly through their leaves (apparently this is 8 times as\nefficient as absorbing them through the roots). Some organic purists frown upon\nthe use of foliar fertilizers as \u201cunnatural\u201d, because it concentrates on\nfeeding the plant rather than the soil. It is sometimes used as a way of\ngrowing plants without building up the soil and this certainly isn\u2019t good\npractice. However it can be useful in some circumstances. It is most often used\nwhen raising transplants, to supply the seedlings with all the nutrients they\nneed for good growth.<\/p>\n\n\n\n Commercial liquid fertilizers<\/strong><\/p>\n\n\n\n The simplest way to foliar\nfeed is with commercially prepared liquid fertilizer such as fish emulsion or\nseaweed. These are convenient and have minimal smell, but are quite expensive.\nA cheaper alternative is to make your own, from compost, manure, comfrey or\nwhatever you have readily available.<\/p>\n\n\n\n It is important to read the\nlabel carefully before you buy any of these, to see what they actually contain.\nThe labels on some of the cheaper products are deliberately deceptive,\nemphasizing their organic ingredients, while hoping you won\u2019t notice that most\nof their nitrogen comes from synthetic sources. You would think fish guts would\nbe cheap enough, but I guess not. <\/p>\n\n\n\n Old fashioned compost\/manure tea<\/strong><\/p>\n\n\n\n I like this for its\nsimplicity. It is easily prepared from locally available materials (a renewable\nresource), doesn\u2019t cost anything and supplies all of the most soluble nutrients\nfound in those materials. The problem with this kind of tea is that it has a\nhorrible sewage-like smell and may contain large quantities of pathogenic bacteria.\nThe anaerobic decomposition is smelly enough to discourage many people from\nmaking it more than once. You wouldn\u2019t want to use it in your house and in\ntowns you could well get complaints from neighbors.<\/p>\n\n\n\n Prepare the tea by filling a\nplastic bucket one third full of composted or aged manure (avoid fresh manure\nas you don\u2019t want to spread too many pathogens), or half full of compost and\ntopping it up with water (larger quantities can be made with woven plastic\nsacks and 50 gallon oil drums). Cover with a tight fitting lid and leave to\nsteep for 7 – 10 days (depending on how warm the weather). The tea is then\nstrained into a bucket and diluted one part tea to 2 parts water (if you have\ntwo more buckets of equal size simply pour a third into each of the other\nbuckets and then fill all three buckets with water). Some people add a \u00bd\nteaspoon of soap per gallon as a wetting agent, to help it stick to leaf\nsurfaces (some leaf surfaces are hard to wet). You can also use molasses for\nthis.<\/p>\n\n\n\n Modern <\/strong>actively aerated\ncompost\/manure tea<\/strong><\/p>\n\n\n\n In recent years the making\nof compost tea has undergone a radical transformation. Those who were repulsed\nby the old stinky anaerobic compost tea now have an alternative in the form of\nactively aerated compost tea or AACT. This is made in a similar way to the old\ncompost tea, with one big difference. Air is bubbled through the liquid for the\nwhole time it is being made. This results in an aerobic tea with only a mild\nearthy smell.<\/p>\n\n\n\n To make this kind of tea you need to be able to bubble air through\nthe liquid for the entire time it is brewing. You can buy commercially made\naerating systems, but it is much cheaper to make your own. All you need is an\naquarium aerator, a three gang valve, some plastic hose and a 5 gallon bucket.\nIf you buy the right parts it probably doesn\u2019t take you any longer to make your\nown than it does to assemble a commercial system.<\/p>\n\n\n\n The compost (or vermicompost\nor aged manure) is put in a bag (a pair of old panty hose works great) to make\na kind of tea bag. This prevents the manure from clogging the hose. This is\nthen left in the bucket for 24 – 48 hours, with air bubbling through it. It\nshould be kept at a temperature of 70 – 80\u00b0F and it should be in the dark. The\nend product should not be offensive in any way. If it is then it didn\u2019t brew\nproperly and you have made old fashioned manure tea.<\/p>\n\n\n\n The finished product is\ndiluted and used like traditional manure tea.<\/p>\n\n\n\n By using your kitchen waste\nto feed the worms you can produce vermicompost, which can then be used to make\ntea to feed your plants and grow vegetables which then go to the kitchen. This\ncreates a nice closed loop that doesn\u2019t require you to buy anything.<\/p>\n\n\n\n Applying foliar fertilizers<\/strong><\/p>\n\n\n\n Plants only absorb nutrients\nthrough their leaves as they need them, so it\u2019s more effective to use frequent\napplications of very dilute fertilizers. If they are applied in too high a\nconcentration they may burn the plants and you will waste nutrients. Don\u2019t\napply foliar fertilizers to water stressed plants, as it may do them more harm\nthan good. In such cases remedy the water stress first and then feed.<\/p>\n\n\n\n The best way to apply foliar fertilizers is\nwith a sprayer, as this enables you to wet both sides of the leaves for maximum\nnutrient absorption. To cover larger areas you can get an injector system that\nattaches to a hose and watering wand. You could also use a hand sprayer or\nbackpack unit normally used for spraying pesticides. If you have nothing else\nyou can use a watering can with a fine rose (though it\u2019s harder to cover the\nundersides of the leaves).<\/p>\n\n\n\n The best time for applying a\nfoliar feed is in early evening, because the nutrients are most easily absorbed\nat night when leaf stomata are open (it is up to 10 times more effective at\nthis time). It also helps if the air is still and humidity is high. Early\nmorning is also good. Ideally the plants shouldn\u2019t get wet again until they\nhave had 24 hours to absorb the nutrients through their leaves (wetting will\nwash off the nutrients). Generally it is better to give several light\napplications, rather than one heavy one.<\/p>\n\n\n\n In less than ideal soils it\nmay be necessary to fertilize several times during the growing season. Perhaps\nbegin with a feed as soon as the plants have recovered from transplanting, to\nget them up and going. Feed them again just before they start developing the\nfood producing part and once again as this part is sizing up. Of course, rather\nthan keeping track of every crop and stage of growth, you could just feed\neverything in the garden every couple of weeks<\/p>\n\n\n\n Don\u2019t harvest and eat green\nleaf crops within 2 weeks of fertilization, as nitrogen rich feeds can\ntemporarily increase the level of toxic nitrates in the plant. Of course you\nwouldn\u2019t want to eat salad greens that have just be sprayed with diluted manure\nanyway.<\/p>\n\n\n\n Applying liquid fertilizers<\/strong><\/p>\n\n\n\n The difference between\nliquid fertilizers and foliar ones is in the manner in which they are absorbed.\nThe same materials are used and for the same purposes. Rather than being\nabsorbed through the leaves, liquid fertilizers are absorbed through the roots in\nthe usual way.<\/p>\n\n\n\n Liquid fertilizers are usually applied with a watering can. You merely pour water on to the soil around the plants individually, as if you were watering them in after transplanting. After applying the fertilizer you then irrigate the whole bed to soak the nutrients down to the root zone<\/p>\n\n\n\n Top dressing<\/strong><\/p>\n\n\n\n Top dressing is another\nmethod of applying fertilizers to growing plants. It usually means sprinkling\nsmall quantities of soluble fertilizers onto the soil around the plants to give\nthem a quick boost. They will be washed down to the root zone by rain or\nirrigation water.<\/p>\n","protected":false},"excerpt":{"rendered":"Plant teas<\/strong>
Green plants can also be made into foliar <\/strong>fertilizer. If a specific nutrient is in short supply you might want to use a plant that accumulates that nutrient. You can also mix different plants of course, or add liquid seaweed.
The usual method of preparation is pretty much the same as for old fashioned compost tea. You fill the plastic bucket with as much foliage as it will hold (best for comfrey, seaweeds, nettles), top it up with water, then cover and leave for 2 – 5 days. Unfortunately these smell just as bad as manure tea.
You may also want to experiment with making aerated teas as described above. These are much less offensive and so more pleasant to work with.
Comfrey<\/strong>: This is best known s a source of potassium, but is also rich in nitrogen, phosphorus, calcium and magnesium. It is especially valued for feeding young plants.
Stinging nettle<\/strong>: A quick source of nitrogen,phosphorus and iron.
Alfalfa<\/strong>: A source of phosphorus.
Horsetail<\/strong>: Biodynamic gardeners believe Horsetail <\/strong>tea increases plants resistance to disease.
Oak bark<\/strong>: Rich in calcium.
Seaweeds<\/strong>: Rich in nitrogen, potassium and many trace elements (wash thoroughly before use to remove salt)
Yarrow<\/strong>: A source of potassium and silica. Some people believe it also increases a plants resistance to disease.
Grass<\/strong>: Lawn clippings are an easily available source of nitrogen. <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n