Those things will rush to seed 99% of the time. Sorry to say it but the best that you can do is use them as scallions.

Martin

If your haviing problems growing onions, you may want to consider creating a bed for them for a future years growth. The soil mix would contain sand as well as good drainage if the soil is heavy. Onions, like most root crops prefer a loose soil high in potash too.

Onions do NOT require high percentage of potash fertilizer. Their initial needs are for phosphate first, and then nitrogen. Potassium is the LEAST required of the NPK trio.

Martin

whoa - thanx Martin for stopping folks from over-doing it.

Am happy to have just added a rich compost mulch this week since we expect afternoon temps as high the 80's this week. Evenings are still be in the 40's/50's - so I figure I may have another harvest of scapes as the plants keep growing at nite, and think days are for blooming.

I assume I should add more compost as a soft top dressing when I see bulbing heads starting to lift above the ground, is that right?

Pdx, if your compost is rich in nitrogen, it will be OK but don't go too wild with it. For fertilizer purposes, normal compost would be considered no higher than 1-1-1. As with all vegetables, the time to apply fertilizer is before or during planting, not afterward. Onions do benefit from a side-dressing of nitrogen about every 3 weeks. Of course, that would have to be either in liquid form or water soluble to be of much immediate use. I don't know if it ever did any good but I used to mulch onions with freshly-cut grass clippings for years.

Any compost mulch added to a garden now is primarily for weed suppression and moisture retention. With onions, the benefit there would be to keep the soil slightly damp to allow pop-up expansion. After the first rain, most soluble nutrients are flushed into the soil as a form of compost tea. What remains would need to be broken down by soil bacteria in order to release their nutrients. You are always fertilizing one year ahead when using compost for mulch.

Martin

The link below mentioned the need for potash for all root crops, and mostly for potatoes.

Here is a link that might be useful: Potash in soil

Repeat, alliums do not need a high potash fertilizer. Initial requirements are a 1-2-1 ratio, such as 10-20-10, at planting time. Then best results obtained by side-dressing with 21-0-0 ammonium sulfate. That would be a combined 31-20-10 with potassium being the smallest number.

Martin

Here is another quote from a web site regarding the need for potash. Even if the ratio is 1-2-1 the soil STILL needs potash, as mentioned above by the contradiction and bending of the rule.

"Phosphorus and potassium requirements are similar to onions. Soil tests are required to determine phosphate and potash requirements. Soil pH, phosphorus and potassium levels should be amended prior to fall planting. Phosphorus and potassium requirements are similar to onions. Phosphate and potash recommendations in this publication are based on Ontario Ministry of Agriculture, Food and Rural Affairs soil tests (See Table 3: Phosphorus Requirements - Vegetables on Mineral Soils, Table 4: Potassium Requirements - Vegetables on Mineral Soils, and Table 5: Phosphorus and potassium Requirements - Vegetables on Muck Soils.) These tables should be used only with OMAF-accredited soil tests. Non-accredited tests may use extractants that pull out different amounts of nutrients, so they will not give correct answers if used with the OMAF tables."

Here is a link that might be useful: Canadian Govt.info on onion and garlic fertilizer requirements

Ksrogers, needing something and needing LOTS of something are two different things. If one were growing onions or potatoes, and heard that they needed LOTS of potash, what NPK should they go looking for? If 10-20-10 were the recommended one, then 5-10-30 would surely be 3 times LOTS better. 0-15-45 would be 50% LOTS better than that. The ultimate LOTS more would be 0-0-60. Then when that someone asks why their onion and potatoes are stunted and looking poorly, you can tell them that they need LOTS more water which will only make the matter worse. What would make it especially ironic is that it would have been your error which caused it in the first place! Remember that it's so much easier to prevent a problem than to correct a problem.

Martin

Martin, the relationships actually are geometric. So 5-10-30 would be _nine_ times lots better, rather than a paltry 3x lots better.

Either way, certainly lots too much potash.

>Onions do benefit from a side-dressing of nitrogen about every 3 weeks.I've always been taught to cut down on the nitrogen once bulbing starts. That something on the order of 5-10-5 is better at that point.

Do you continue with that nitrogen schedule right through harvest?