Fertilizing for the Farm and Garden
Before we talk about fertilizing for the home garden, I wanted to let folks know a little about our fertilizing regimen and the products we use. You could spend a career in soil science and still not know it all! Here's our take:
Fertilizing on Bellair Farm
Bellair's Nutrient Management Plan
Our nutrient management plan is the backbone to managing soil and plant health on the farm. In early 2020, we worked with a Nutrient Management Specialist at the Department of Conservation and Recreation to create a plan for the farm. Using his expertise, we were able to hone in at the crop-family level in a way that we had never done before. Anecdotally, this more intensive planning is yielding visible results for us. We are excited to continue to to tweak our methods for future years! Currently, we start with soil tests: we sample each field and send them off to a lab for the results. Next, we make a breakdown of how many beds of each type of crop (solenaceous or cucurbit, etc) go into each field (this is the "Crop Plan" that I keep referring to). After that, it is a complicated series of spreadsheet formulas that convert bed space into acreage and then takes into account crop needs, active nutrient amounts per fertilizer product, and present field nutrients to spit out a quantity of fertilizer types for each bed.
Types of Fertilizer
We focus primarily on the three macro-nutrients of Nitrogen, Phosphorous, and Potassium, as well as on three micronutrients, Boron, Sulfur, and Zinc.
Nitrogen: Organic versions of fertilizer can come from lots of different animal products: blood or feather meal, manure, etc. We love a manure-based product as we feel it contains lots of micronutirents that aren't necessarily measurable. We use a product called Clarus, a chicken litter product, for most of our N needs and supplement with Naturesafe Landscape, a 7-7-2 with multiple nitrogen sources. We like applying two types of N because it might help the plant with nutrient uptake from different timed releases or source forms of the nitrogen.
Phosphorous: This nutrient can be organically sourced as a mined material (soft rock phosphate) or as an animal product (bone meal). In our experience, the rock source is really not very effectively available to plants. We much prefer bone meal in a granulated form so it's not powdery.
Potassium: This nutrient can be organically sourced as a mined material. We use a minimally processed evaporative-collection-type potassium product.
Micronutrients: For sulphur, zinc, and boron, which we are very low on in our fields, we apply these specifically. For other micronutrients, we rely on already-available quantities (our red clay is super iron-rich) and also supplement with high-diversity liquid fertilizers that we use in the greenhouse and for fertigation (fertilizing through irrigation lines).
Applying fertilizer
In general, there are thee ways to apply fertilizer: broadcasting (just throwing it all over) and side-dressing (putting it in a line beside a row of plants), and liquid application either by spraying on leaves or at the root level. We do all of the above to try to meet the needs of our diverse crops!
Fertilizers and your Garden
You may have read the above info and now your head is spinning. Don't worry! We are professional farmers and that's why it matters that we get into the minutia of it. Even for us, there is a point of limited return on research in this realm: unless measurable yield improvements are possible, it doesn't make sense to spend oodles of time in the details. Here are some tips I have for home gardeners, from my experience growing on a garden and farm scale for over a decade:
1) Compost is king: compost contains a whole host of micronutrients and living organisms that will benefit your plants in immeasurable ways. The only reason we don't use it on a large scale is it is way too expensive for 23 acres! Here are some local businesses that convert leaf litter and other rubbish into wonderful (and for the garden-affordable) composts! Black Bear Compost, Panorama Paydirt
2) Liquid feeding is easy and effective: To boost tomato fruiting after the plant has already grown a great deal, it's hard to beat a liquid fertilizer. They are obviously water soluble so easily accessed by plants even if applied after planting. Most liquids will need to be diluted to a certain strength that will be different for foliar (leaf) feeding or regular root feeding. Too strong and you may burn your plants
3) Don't sweat the small stuff -- sure, you can get soil tests done (often for free!) and write up a whole management plan, but it probably isn't necessary. In general, a heavy compost application (4-6 inches over your entire garden) every 2-3 years is probably more than sufficient with some liquid fertilizing.
4) Cover crops are for gardens, too! To take your garden to the next level, try a cover crop! This can have 2 effects: 1, you are feeding the soil life with this crop. You will see noticeable differences in plant health and soil tilth other time. 2, you can use the cover crop as a diagnostic tool for nutrient issues. If the cover crop is stunted in certain areas or the whole patch has yellowing or purpling to the leaves, these are indicators of larger nutrient issues and provide you with great evidence towards getting to the bottom of it! Good cover crops for summer-grown gardens are oats and winter peas, but there are so many to choose from!